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B1 suffix #3,000 most common 10 min read

～科

Top 3,000

Practice it Examples Notes & Tips ～科 in 30 Seconds

Explanation ～科 in your Level:

At the A1 level, you only need to know ～科 (ka) as part of a few very common words. The most important one is 理科 (rika), which means 'science' as a school subject. You might also see 教科 (kyouka) meaning 'subject' in general. At this stage, treat them as single vocabulary words rather than worrying about the suffix itself. Just remember that when you see this character, it often has something to do with school or studying. You might also see it on a map for a 'Dentist' (歯科 - shika), which is very useful if you have a toothache while traveling!

At the A2 level, you should start recognizing ～科 (ka) as a suffix used for medical departments. When you feel sick, you need to know which department to go to. Common ones include 内科 (naika) for internal medicine (colds, stomach aches) and 外科 (geka) for injuries. You will also see this suffix in the word 学科 (gakka), which refers to a department or course of study in a college or vocational school. You should be able to say things like 'I am going to the eye doctor' (眼科に行きます - ganka ni ikimasu).

At the B1 level, you are expected to use ～科 (ka) more precisely. You should distinguish it from 課 (ka), which is used for business sections. You should also become familiar with more specific medical departments like 小児科 (shounika) for pediatrics or 皮膚科 (hifuka) for dermatology. In academic settings, you should be able to describe your major using ～学科 (gakka). You will also start encountering this suffix in the context of biological families in textbooks or museums, such as ネコ科 (neko-ka) for the cat family.

At the B2 level, ～科 (ka) appears in more complex compound nouns and formal contexts. You will see it in terms like 専科 (senka) meaning a specialized course, or 本科 (honka) meaning a regular course. You should be comfortable reading medical forms that list various sub-specialties like 循環器内科 (junkaanki-naika) for cardiology. You should also understand the nuance of how 科 functions in administrative hierarchies within universities and how it differs from 部 (bu) or 系 (kei). Your ability to use these terms correctly in a professional or academic environment is key.

At the C1 level, you should have a deep understanding of the historical and linguistic roots of ～科 (ka). You can discuss the nuances of scientific classification and use the term in academic writing. You will encounter specialized terms like 百科事典 (hyakkajiten) for encyclopedia (literally 'book of a hundred branches') and understand how 科 contributes to the meaning of 'comprehensive knowledge'. You should also be aware of legal and bureaucratic uses of the suffix in government regulations regarding the establishment of new academic departments or medical facilities.

At the C2 level, your mastery of ～科 (ka) is near-native. You can effortlessly navigate the most technical medical or scientific literature where 科 is used in highly specific taxonomic or administrative ways. You understand subtle distinctions in how different institutions might use 科 vs. 類 (rui) or 門 (mon) in classification systems. You can also appreciate the wordplay or historical references involving the kanji in literature. Your use of the suffix in formal speeches or complex negotiations regarding organizational restructuring is precise and sophisticated.

Practice it Examples Notes & Tips

～科 in 30 Seconds

A suffix meaning 'department' or 'branch' used in medical, academic, and biological contexts.
Essential for identifying medical specialties like internal medicine (naika) or dentistry (shika).
Used in universities to name specific departments (gakka) within a faculty (gakubu).
Acts as the taxonomic rank for 'Family' in biological classification (e.g., neko-ka for cats).

The suffix ～科 (ka) is a fundamental building block in the Japanese language, primarily used to denote a specific branch of knowledge, a department within a medical facility, or a division of study. Derived from the kanji representing 'grain' (禾) and a 'measuring ladle' (斗), the original concept involves measuring and categorizing harvest items, which evolved into the broader meaning of classification and specialization. In modern Japan, you will encounter this suffix most frequently when navigating the healthcare system or discussing academic subjects. It acts as a classifier that tells the listener exactly what type of expertise is being discussed.

Medical Context: In hospitals and clinics, ～科 identifies the medical specialty. For example, if you have a stomach ache or a cold, you visit the 内科 (naika) or Internal Medicine department. If you have a skin rash, you look for the 皮膚科 (hifuka) or Dermatology department. This suffix is essential for identifying where to go for treatment.

風邪を引いたので、近くの内科に行ってきました。
(Kaze o hiita node, chikaku no naika ni itte kimashita.)
Since I caught a cold, I went to a nearby internal medicine clinic.

Academic Context: In schools, especially from elementary through high school, ～科 is used in the word 教科 (kyouka), meaning 'subject.' At the university level, it denotes a specific department or major, such as 英文科 (eibunka) for the Department of English Literature. It signifies a structured branch of academic inquiry.

彼は大学で工学科を専攻しています。
(Kare wa daigaku de koungakka o senkou shite imasu.)
He is majoring in the Department of Engineering at university.

Beyond medicine and school, ～科 is also the standard suffix for biological families in taxonomy. For instance, the cat family is known as ネコ科 (neko-ka). This usage reinforces the idea of ～科 as a tool for systematic categorization. Understanding this suffix allows learners to decipher the purpose of various buildings and departments without necessarily knowing every specific kanji combination, as the presence of 科 immediately signals a specialized division of some kind.

Biological Classification: In the hierarchy of biological classification (Kingdom, Phylum, Class, Order, Family, Genus, Species), 科 (ka) corresponds to the 'Family' level. This makes it a scientific term used by researchers and nature enthusiasts alike.

ライオンはネコ科の動物です。
(Raion wa neko-ka no doubutsu desu.)
Lions are animals of the cat family.

In summary, ～科 is an indispensable suffix for navigating professional and academic environments in Japan. Whether you are seeking a doctor, choosing a university major, or studying biology, this character acts as the primary marker for 'department' or 'category'. Its consistent usage across these diverse fields makes it a high-frequency term for intermediate learners to master, as it provides a structural framework for organizing Japanese vocabulary related to expertise and specialization.

Using ～科 (ka) in a sentence is relatively straightforward because it functions as a suffix that attaches directly to the end of a noun describing a field. However, there are nuances in how it interacts with verbs like 'to go' (iku), 'to major in' (senkou suru), and 'to belong to' (shozoku suru). Because ～科 often refers to a physical place (a department in a hospital) or an abstract concept (a field of study), the particles used are crucial for clarity.

Going to a Medical Department: When you need to visit a doctor, you usually use the particle に (ni) or へ (e) to indicate the destination. You can say you are going to the 'Internal Medicine' department directly, which implies you are going to see a doctor of that specialty.

目が痛いので、午後から眼科に行きます。
(Me ga itai node, gongo kara ganka ni ikimasu.)
My eyes hurt, so I'm going to the ophthalmology department (eye doctor) this afternoon.

Academic Affiliation: In a university setting, students are often 'in' a department. The verb 在籍する (zaiseki suru - to be enrolled) or simply the copula です (desu) can be used. When describing a major, ～科の学生 (ka no gakusei) is a common way to identify yourself.

私は経済学部の経営学科に所属しています。
(Watashi wa keizaigakubu no keieigakka ni shozoku shite imasu.)
I belong to the Department of Business Administration in the Faculty of Economics.

Another common usage is in the context of school subjects, specifically 理科 (rika - science) and 教科 (kyouka - subject). In elementary school, 'Rika' is the name of the science class. In high school, this is further subdivided into specialized 'ka' like 物理 (butsuri - physics), though the suffix 'ka' is often dropped in casual conversation about classes, it remains in formal curriculum descriptions.

Identifying Subjects: When asking someone what their favorite subject is, you use 'kyouka'. This refers to the broad categories of study in the school curriculum.

一番好きな教科は何ですか？
(Ichiban suki na kyouka wa nan desu ka?)
What is your favorite subject?

Finally, when using ～科 in biological descriptions, it usually follows the name of a representative animal or plant. This is highly formal and scientific. You will see this in zoos, botanical gardens, and documentaries. It is rarely used in daily conversation unless you are discussing specific animal traits or classifications.

イヌ科の動物には、オオカミやキツネも含まれます。
(Inu-ka no doubutsu ni wa, ookami ya kitsune mo fukumaremasu.)
Animals of the canine family also include wolves and foxes.

The suffix ～科 (ka) is ubiquitous in the Japanese physical environment. If you walk down any commercial street or enter a multi-tenant building near a train station, you will see numerous signs for medical clinics. These signs are the most common place to see 'ka' in the wild. For example, a sign might say '田中歯科' (Tanaka Dental) or '佐藤内科クリニック' (Sato Internal Medicine Clinic). In these contexts, ～科 is not just a suffix; it is a primary identifier of the service provided.

At the Hospital: In large hospitals (byouin), you will hear announcements like '内科でお待ちの田中様...' (Mr. Tanaka, waiting in the Internal Medicine department...). The reception desk will have signs pointing to different wings designated by their ～科 names. It is also common to see these terms on health insurance forms and medical receipts.

次は皮膚科の診察室へお進みください。
(Tsugi wa hifuka no shinsatsushitsu e o-susumi kudasai.)
Please proceed to the dermatology examination room next.

In University Life: During the university entrance exam season (juken), you will hear students discussing which 学科 (gakka) they are applying to. On campus, students introduce themselves by their year and their department. For example, '法学部法律学科の2年生です' (I am a second-year student in the Department of Law, Faculty of Law).

この大学の物理学科は非常に有名です。
(Kono daigaku no butsurigakka wa hijouni yuumei desu.)
The physics department of this university is very famous.

You will also encounter ～科 in media, particularly in educational programs or news reports about health and science. News anchors might mention findings from the 'American Academy of Pediatrics' (アメリカ小児科学会). In nature documentaries, the narrator will use ～科 to classify the species being shown, such as 'イタチ科' (weasel family) or 'バラ科' (rose family). This suffix provides a sense of authority and precision to the language being used.

In Job Hunting: When looking at job listings for teachers or researchers, requirements will often state that the applicant must have graduated from a specific 学科 (gakka). For example, '理科の教員免許' (Science teacher license) specifically uses the 'ka' suffix to define the scope of the qualification.

彼は教育学科を卒業して、先生になりました。
(Kare wa kyouikugakka o sotsugyou shite, sensei ni narimashita.)
He graduated from the Department of Education and became a teacher.

One of the most frequent mistakes for Japanese learners is confusing 科 (ka) with other kanji that are also pronounced 'ka', most notably 課 (ka). While both can be translated as 'department' or 'section' in English, their usage is strictly segregated by context. Using the wrong 'ka' can make a sentence nonsensical or indicate a lack of understanding of Japanese organizational structures.

Mistake 1: Confusing 科 (ka) with 課 (ka): 科 (ka) is for academic or medical branches. 課 (ka) is for administrative sections in a company or government office. For example, 'Sales Department' is 営業課 (eigyou-ka), never 営業科. Conversely, 'Internal Medicine' is 内科 (naika), never 内課.

❌ 私は営業科で働いています。
✅ 私は営業課で働いています。
(I work in the Sales Section.)

Mistake 2: Redundant Suffixes: Learners sometimes try to add 'department' (busho or gakka) to a word that already contains 'ka'. For example, saying 内科学科 (naika-gakka) is redundant. 'Naika' already means 'Internal Medicine Department'.

❌ 歯科科に行きます。
✅ 歯科に行きます。
(I am going to the dentist.)

Another error involves the pronunciation of specific medical departments. While 'ka' is the standard reading, some words like 産婦人科 (sanfujinka) are quite long and beginners often trip over the 'n-jin-ka' sequence. It is important to treat these as single vocabulary items rather than just a prefix attached to words you know. Also, be careful not to use 'ka' when referring to a person. A doctor is a 医者 (isha) or 先生 (sensei), not a 'ka'. You go to the 'ka' to see the 'sensei'.

Mistake 3: Misusing with People: You cannot call a person a 'ka'. You can say 'The doctor of the internal medicine department' (内科の先生), but you cannot just point at a doctor and say 'He is a Naika'.

❌ 彼は外科です。
✅ 彼は外科医です。
(He is a surgeon - gekai.)

In Japanese, there are several words and suffixes that translate to 'department' or 'section' in English. Choosing the right one depends entirely on the organization's structure. Understanding the hierarchy of these terms—部 (bu), 科 (ka), and 課 (ka)—is key to sounding natural and professional.

科 (ka) vs 課 (ka): As mentioned before, 科 is for academic/medical fields (e.g., 眼科 - Ophthalmology), while 課 is for administrative sections (e.g., 人事課 - HR Section). In a large organization, a 部 (bu - Department) is usually larger than a 課 (ka - Section).

部 (bu): This represents a large division. In a university, 学部 (gakubu) is a 'Faculty' (like the Faculty of Arts). Underneath a 学部, you will find several 学科 (gakka) or departments. So, 部 is the macro-level and 科 is the micro-level.

文学部の英文学科。
(The Department of English Literature in the Faculty of Letters.)

系 (kei): This suffix means 'system' or 'lineage'. In academic contexts, it refers to a group of related departments. For example, 理系 (rikei) refers to the 'Science stream' or 'STEM fields', while 文系 (bunkei) refers to the 'Humanities stream'. It is broader than 科.

There are also more modern terms like コース (koosu - course) or 専攻 (senkou - major) which are used interchangeably with 学科 (gakka) in universities. However, 学科 remains the official designation on diplomas and certificates. In the medical field, there is no real alternative to 科; it is the standard nomenclature for all medical specialties in Japan. Even in specialized clinics, the 'ka' suffix is almost always present in the name to comply with medical advertising regulations.

Summary of Hierarchy: 1. 学部 (Gakubu): Faculty (Big)
2. 学科 (Gakka): Department (Medium)
3. 講座 (Kouza): Chair/Lecture (Small)

How Formal Is It?

Fun Fact

The '斗' (ladle) part of the kanji is also the same character used for the Big Dipper constellation in Japanese (Hokuto Shichisei), implying a sense of measurement and order.

Pronunciation Guide

UK /kə/

US /kɑː/

Japanese is a pitch-accent language. In words ending in ～科, the 'ka' is usually part of a low-pitch or tail-flat pattern depending on the word (e.g., naika often drops after 'nai').

Rhymes With

ka (question particle) ka (mosquito) ka (lesson/section - different kanji) ka (price/value - different kanji) ka (fire/Tuesday - different kanji) ka (fruit - different kanji) ka (transformation - different kanji) ka (below - different kanji)

Common Errors

Pronouncing it like 'kay'.
Elongating the vowel to 'kaa'.
Stressing it too heavily compared to the root word.
Confusing the pitch with 'ka' (the question particle).
Muffling the 'k' sound.

Difficulty Rating

Reading 2/5

The kanji is relatively simple and appears very frequently in public signs.

Writing 3/5

The 'ladle' and 'grain' radicals are easy to mix up if not practiced.

Speaking 1/5

The 'ka' sound is one of the easiest for English speakers to pronounce.

Listening 2/5

Easy to hear, but must be distinguished from 'ka' (lesson) in fast speech.

What to Learn Next

Prerequisites

医者 (Doctor) 学校 (School) 勉強 (Study) 病気 (Illness) 大学 (University)

Learn Next

学部 (Faculty) 専門 (Specialty) 受診 (Medical consultation) 専攻 (Major) 分類 (Classification)

Advanced

亜科 (Subfamily) 分科会 (Subcommittee) 百科全書 (Encyclopedia) 科挙 (Imperial examination)

Grammar to Know

Suffixing Nouns

Adding 科 to the end of a field name to create a department name (e.g., 英語 + 科 = 英語科).

Compound Kanji Nouns

Combining multiple specialties, like 産婦人科 (San-fu-jin-ka).

Particle に with Verbs of Motion

Using 'ka + に + iku' to indicate going to a specific department.

Particle の for Possession/Affiliation

Using 'ka + の + gakusei' to indicate being a student of that department.

Taxonomic Naming

Using Katakana animal name + 科 for biological families.

Examples by Level

私は理科が好きです。

I like science.

理科 (rika) is a noun meaning 'science' as a school subject.

これは何の教科ですか？

What subject is this?

教科 (kyouka) means 'subject' or 'curriculum item'.

歯科はどこですか？

Where is the dental clinic?

歯科 (shika) refers to the dental department or clinic.

明日は理科のテストがあります。

There is a science test tomorrow.

理科 (rika) functions as a noun.

図工と理科、どちらが好きですか？

Which do you like better, arts and crafts or science?

Comparing two school subjects.

駅の前に歯科があります。

There is a dental clinic in front of the station.

Using 'arimasu' to indicate existence.

理科の本を読みます。

I read a science book.

理科 (rika) modifies the noun 'hon'.

教科書を開けてください。

Please open your textbook.

教科書 (kyoukasho) is 'textbook', containing the 'ka' kanji.

風邪を引いたので、内科に行きます。

I have a cold, so I am going to the internal medicine department.

内科 (naika) is the standard place for common illnesses.

弟は小児科で診てもらいました。

My younger brother was seen at the pediatrics department.

小児科 (shounika) means pediatrics.

この大学には、多くの学科があります。

This university has many departments.

学科 (gakka) refers to an academic department.

外科の先生はとても優しいです。

The doctor in the surgery department is very kind.

外科 (geka) refers to surgery.

眼科で新しい眼鏡を作りました。

I got new glasses made at the ophthalmology clinic.

眼科 (ganka) is for eye-related issues.

彼は工学科の学生です。

He is a student in the engineering department.

工学科 (kougakka) is the department of engineering.

耳鼻科は二階にあります。

The ENT (Ear, Nose, and Throat) clinic is on the second floor.

耳鼻科 (jibika) is a common abbreviation for ENT.

皮膚科で薬をもらいました。

I got medicine at the dermatology clinic.

皮膚科 (hifuka) is for skin issues.

明日の朝、産婦人科の予約が入っています。

I have an appointment at the OBGYN clinic tomorrow morning.

産婦人科 (sanfujinka) combines obstetrics and gynecology.

トラはネコ科の中で最大の動物です。

The tiger is the largest animal in the cat family.

ネコ科 (neko-ka) uses the suffix for biological classification.

彼は経済学部の経営学科に所属しています。

He belongs to the Department of Business Administration in the Faculty of Economics.

Showing the hierarchy of Faculty (bu) and Department (ka).

この病院には精神科もあります。

This hospital also has a psychiatry department.

精神科 (seishinka) refers to psychiatry.

どの学科を専攻するか迷っています。

I am undecided about which department to major in.

専攻する (senkou suru) means to major in.

彼は理科の教員免許を持っています。

He has a teaching license for science.

理科 (rika) as a specific teaching subject.

アレルギーがあるので、耳鼻咽喉科へ行きました。

I have allergies, so I went to the ENT department.

耳鼻咽喉科 (jibinkouka) is the full name for ENT.

この植物はバラ科に属しています。

This plant belongs to the rose family.

属している (zoku shite iru) means to belong to a category.

その大学の工学部電気電子工学科は、最先端の研究施設を誇っている。

The Department of Electrical and Electronic Engineering in the Faculty of Engineering at that university boasts state-of-the-art research facilities.

Complex academic compound noun.

循環器内科の専門医に相談することをお勧めします。

I recommend consulting a specialist in the cardiology department.

循環器内科 (junkaanki-naika) is a sub-specialty.

彼は本科を卒業した後、さらに専科で一年間学びました。

After graduating from the regular course, he studied for another year in a specialized course.

Distinction between 本科 (honka) and 専科 (senka).

この論文は、社会科学科の紀要に掲載されました。

This paper was published in the bulletin of the Department of Social Sciences.

社会科学科 (shakaikagakka) refers to Social Sciences.

形成外科で傷跡の治療を受けることにした。

I decided to undergo treatment for the scar at the plastic surgery department.

形成外科 (keiseigeka) refers to plastic/reconstructive surgery.

彼は生物学科の教授として、海洋生物の研究に没頭している。

As a professor in the biology department, he is immersed in the study of marine life.

生物学科 (seibutsu-gakka) refers to Biology department.

新設されたデータサイエンス学科への応募が殺到している。

Applications are flooding into the newly established Data Science department.

新設 (shinsetsu) means newly established.

心療内科は、ストレスによる体の不調を扱う診療科です。

Psychosomatic medicine is a clinical department that deals with physical ailments caused by stress.

心療内科 (shinryou-naika) is psychosomatic medicine.

百科事典を紐解けば、人類の知識の集積に圧倒されるだろう。

If you open an encyclopedia, you will be overwhelmed by the accumulation of human knowledge.

百科事典 (hyakkajiten) uses 'ka' to mean 'many branches'.

文部科学省は、新たな教育課程の指針を発表した。

The Ministry of Education, Culture, Sports, Science and Technology announced new curriculum guidelines.

文部科学省 (Monbu-kagaku-shou) includes 'science' (kagaku).

彼は比較文化学科において、東洋と西洋の価値観の相違を研究している。

In the Department of Comparative Culture, he is researching the differences between Eastern and Western values.

High-level academic department name.

この病院の救急科は、24時間体制で重症患者を受け入れている。

The emergency department of this hospital accepts severely ill patients 24 hours a day.

救急科 (kyuukyuuka) is the emergency department.

彼は数理科学科の博士課程を修了し、ポスドクとして採用された。

He completed the doctoral program in the Department of Mathematical Sciences and was hired as a postdoc.

数理科学科 (suurikagakka) is Mathematical Sciences.

その博物館の標本は、科・属・種の順に厳密に分類されている。

The specimens in that museum are strictly classified in the order of family, genus, and species.

Technical use in taxonomy.

麻酔科医の不足が、地方病院における手術の遅延を招いている。

A shortage of anesthesiologists is causing delays in surgeries at regional hospitals.

麻酔科医 (masuika-i) means anesthesiologist.

彼は専科大学で、特定の技能を磨くことに専念した。

He concentrated on honing specific skills at a vocational college.

専科大学 (senka-daigaku) refers to a specialized/vocational college.

学問の分科が進むにつれ、領域横断的な研究の重要性が増している。

As the specialization of academic disciplines progresses, the importance of cross-disciplinary research is increasing.

分科 (bunka) means specialization or branching of disciplines.

この地域一帯の植生は、ブナ科の樹木によって支配されている。

The vegetation throughout this region is dominated by trees of the Fagaceae (beech) family.

Formal botanical classification.

彼は政治経済学部の政治学科主任として、学内の改革を断行した。

As the head of the Department of Political Science in the Faculty of Political Science and Economics, he carried out internal reforms.

High-level administrative title.

放射線科における画像診断技術の向上は、早期発見に大きく貢献している。

The improvement of imaging diagnostic technology in the radiology department is contributing significantly to early detection.

放射線科 (houshasenka) is radiology.

その研究者は、新種の昆虫がどの科に属するかを同定するのに数ヶ月を要した。

The researcher took several months to identify which family the new species of insect belonged to.

同定する (doutei suru) means to identify/classify.

彼は法学研究科の特別研究員として、国際法の再解釈に取り組んでいる。

As a special researcher in the Graduate School of Law, he is working on the reinterpretation of international law.

法学研究科 (hougaku-kenkyuuka) refers to a graduate school of law.

各診療科の連携を強化することで、包括的な患者ケアを実現する。

By strengthening the cooperation between various clinical departments, we achieve comprehensive patient care.

診療科 (shinryouka) means clinical departments.

この百科全書的な知識の網羅性は、編纂者の執念の賜物である。

The comprehensiveness of this encyclopedic knowledge is the result of the editor's tenacity.

百科全書的 (hyakkazenshoteki) means encyclopedic.

Common Collocations

内科を受診する

学科を専攻する

～科に属する

新設の学科

主要な教科

専門の診療科

～科の教員

百科事典を引く

外科手術

文科系

Common Phrases

内科

— Internal medicine. The most common department for general illness.

まずは内科に行ってください。

外科

— Surgery department. Used for physical injuries or operations.

怪我をしたので外科へ行った。

歯科

— Dentistry. Often found in private clinics.

歯科で虫歯の治療をする。

眼科

— Ophthalmology. For eyes and vision.

コンタクトレンズのために眼科へ行く。

皮膚科

— Dermatology. For skin, hair, and nails.

肌荒れがひどいので皮膚科に行く。

小児科

— Pediatrics. For children's health.

子供を小児科に連れて行く。

理科

— Science. A core school subject.

理科の実験は楽しい。

学科

— Department. A specific major in university.

あなたの学科は何ですか？

教科書

— Textbook. Used in schools.

教科書を忘れないでください。

耳鼻科

— ENT (Ear, Nose, Throat). Short for 耳鼻咽喉科.

花粉症で耳鼻科が混んでいる。

Often Confused With

～科 vs 課 (ka)

Used for sections in an office (e.g., Personnel Section). 科 is for fields of knowledge.

～科 vs 個 (ko)

A counter for small objects. Sounds similar but used for counting.

～科 vs 化 (ka)

A suffix meaning '-ization' (e.g., henka - change). Different kanji and meaning.

Idioms & Expressions

"百科事典のような"

— To have a vast, broad range of knowledge like an encyclopedia.

彼の知識は百科事典のようだ。

Common

"文科系女子"

— A girl who prefers humanities, arts, or indoor activities (slang/cultural).

彼女は典型的な文科系女子だ。

Informal

"理科系男子"

— A guy who is logical, tech-savvy, or likes science (slang/cultural).

彼は理科系男子で、機械に詳しい。

Informal

"お家芸の～科"

— A specialty or 'forte' that a specific group is famous for.

それは彼の所属する学科のお家芸だ。

Colloquial

"専科を立てる"

— To establish a specialized field or focus on one thing exclusively.

この店はカレーの専科を立てている。

Journalistic

"科を跨ぐ"

— To involve multiple departments or specialties.

その問題は複数の診療科を跨いでいる。

Professional

"門外漢"

— An outsider; someone outside the 'gate' or department of expertise (uses 'mon' but related to the concept of 'ka').

私はその分野については門外漢です。

Formal

"科を分ける"

— To categorize or branch out into different specialties.

研究が進み、さらに細かく科を分けることになった。

Academic

"理科離れ"

— The phenomenon of young people losing interest in science.

最近の若者の理科離れが問題になっている。

Social/News

"科の誇り"

— The pride of one's department or major.

学科の誇りにかけて、このプロジェクトを成功させる。

Spirited

Easily Confused

～科 vs 内科 (Naika)

Beginners might confuse it with 'inside' (nai).

Naika specifically refers to internal medicine, not just being 'inside'.

風邪の時は内科に行きます。

～科 vs 外科 (Geka)

Might be confused with 'outside' (ge/soto).

Geka refers to surgery (external treatment/cutting), not just the outside world.

怪我をしたので外科へ行きました。

～科 vs 教科 (Kyouka)

Sounds like 'strengthening' (kyouka - different kanji).

教科 refers to a school subject; the other refers to making something stronger.

得意な教科は数学です。

～科 vs 理科 (Rika)

Sounds like the common female name 'Rika'.

Context usually clarifies if it's the subject 'Science' or a person.

理科の先生は厳しい。

～科 vs 専攻 (Senkou)

Often used with 'gakka' but is a verb/noun itself.

Senkou is the 'act' of majoring; Gakka is the 'department' you major in.

私の専攻は経済学科です。

Sentence Patterns

[Subject] は [Subject] が好きです。

私は理科が好きです。

[Illness] なので、[Specialty]科に行きます。

目が痛いので、眼科に行きます。

[University] の [Department]科を専攻しています。

東京大学の経済学科を専攻しています。

[Animal] は [Family]科の動物です。

トラはネコ科の動物です。

[Specialty]科の専門医に診てもらう。

循環器内科の専門医に診てもらう。

百科事典で[Topic]を調べる。

百科事典で日本の歴史を調べる。

[Field]の分科が進んでいる。

現代科学の分科が進んでいる。

[Organization]の[Department]科主任。

医学部の外科主任。

Word Family

Nouns

学科 (gakka - department)

教科 (kyouka - subject)

理科 (rika - science)

百科 (hyakka - many branches/all subjects)

診療科 (shinryouka - clinical department)

Verbs

分科する (bunka suru - to branch out/subdivide)

Adjectives

教科書的な (kyoukashoteki na - textbook-like/standard)

学部 (gakubu - faculty)

研究室 (kenkyuushitsu - lab/office)

専門 (senmon - specialty)

病院 (byouin - hospital)

大学 (daigaku - university)

How to Use It

frequency

Extremely high in medical and academic settings.

Common Mistakes

Using 科 for office sections. → Using 課 (ka).
You work in the 'Eigyou-ka' (営業課 - Sales Section), not 'Eigyou-ka' (営業科). The latter implies an academic study of sales.
Saying 'Naika-san' to a doctor. → Saying 'Naika no sensei'.
You cannot personify the department suffix. Address the person as 'sensei' or use the 'ka' to describe their affiliation.
Confusing 'Rika' (Science) with 'Rekishi' (History). → Using 'Rika' for science only.
Both start with 'Ri', but 'Rika' is the 'branch of logic/science'. History is 'Rekishi'.
Adding an extra 'ka' to 'Gakka'. → Just saying 'Gakka'.
Learners sometimes say 'Keieigakka-ka' thinking they need to add 'department' twice. 'Gakka' already includes it.
Pronouncing 'Naika' as 'Nay-ka'. → Pronouncing it 'Nah-ee-kah'.
The 'ai' sound in Japanese is like 'eye'. Mispronouncing it can make it hard for locals to understand which clinic you need.

Tips

Medical Navigation

Memorize the 'ka' for your common ailments before traveling to Japan. Knowing 'Naika' (Internal), 'Ganka' (Eye), and 'Shika' (Dental) can save you a lot of stress in an emergency.

Radical Recognition

Notice the '禾' (grain) radical. This appears in many words related to 'order' or 'tax' (like 税), helping you remember that 科 is about organized systems.

Academic Introduction

When introducing yourself to Japanese students, say '[University] no [Major]ka no [Year]sei desu'. It's the most professional way to identify your academic background.

School Subjects

In Japan, 'Rika' (Science) and 'Shakai' (Social Studies) are the two main non-language/math subjects in elementary school. 'Rika' uses our 'ka' suffix!

The 'Ka' Pitch

Be careful not to raise the pitch of 'ka' at the end of a department name, or it might sound like you are asking a question about the root word.

Stroke Order

The stroke order for the '斗' part is: top dot, horizontal line, vertical line, then the long diagonal. Getting this right makes the kanji look balanced.

Hospital Announcements

In big hospitals, they call names by department. Listen for '[Specialty]-ka de omachi no...' to know when it's your turn.

Animal Families

If you like visiting zoos, look for the 'ka' on the placards. It's a great way to learn scientific categorization in Japanese.

Department Store vs Department

A department store is 'Depaato'. A medical/academic department is 'Ka'. Don't mix them up; you can't buy shoes in a 'Naika'!

Business vs Academic

Always double-check your emails. If you are writing to a professor, use 'Gakka' (学科). If you are writing to a company manager, use 'Ka' (課).

Memorize It

Mnemonic

Think of a 'Ladle' (斗) measuring 'Grain' (禾) into different 'Departments'. Each scoop goes into a different 'ka'.

Visual Association

Visualize a hospital map where every room is a box (category) being measured out by a doctor with a ladle.

Word Web

Science (理科) Department (学科) Dentist (歯科) Internal Med (内科) Surgery (外科) Subject (教科) Pediatrics (小児科) Encyclopedia (百科)

Challenge

Try to find 5 different '～科' signs the next time you look at a Japanese street view or visit a Japanese city. Write down what each one does.

Word Origin

The kanji 科 comes from the combination of '禾' (grain/rice plant) and '斗' (a measuring ladle). Originally, it referred to the act of measuring and grading grain into different classes or categories.

Original meaning: To measure grain; classification; class.

Sino-Japanese (On-yomi: Ka).

Cultural Context

When discussing 'Seishinka' (Psychiatry), be aware that mental health still carries some stigma in Japan, though it is rapidly changing.

In English, we say 'Department of...' or '...istry'. In Japanese, you just add 'ka' to the end. It's much more consistent than English suffixes like -ology, -ics, or -istry.

The 'White Tower' (Shiroi Kyoto) - A famous drama about the internal politics of a hospital 'Geka' (Surgery) department. Monbu-kagaku-shou (MEXT) - The government ministry that oversees all 'ka' in schools. Gakkyuu Ou (Class King) - Manga/Anime references to school subjects.

Practice in Real Life

Real-World Contexts

At a Hospital

内科はどこですか？
皮膚科の予約をしたいです。
外科の先生に相談します。
診療科を確認します。

At University

何学科ですか？
経済学科を専攻しています。
学科の事務室に行きます。
新しい学科ができました。

At School

理科の教科書。
好きな教科は何？
理科の実験室。
五教科のテスト。

Biological Discussion

ネコ科の動物。
バラ科の植物。
科と属の違い。
新しい科に分類される。

Reading an Encyclopedia

百科事典で調べる。
あらゆる科を網羅する。
分科的な知識。
百科全書を読む。

Conversation Starters

"大学ではどの学科を専攻していましたか？ (What department did you major in at university?)"

"子供の頃、一番好きだった教科は何ですか？ (What was your favorite subject when you were a child?)"

"近くにいい皮膚科を知っていますか？ (Do you know a good dermatology clinic nearby?)"

"理系ですか、それとも文系ですか？ (Are you a science person or a humanities person?)"

"ネコ科の動物の中で何が一番好きですか？ (Which animal in the cat family do you like best?)"

Journal Prompts

今日、病院のどの科に行きましたか？そこで何をしましたか？ (Which department of the hospital did you go to today? What did you do there?)

もし大学に戻れるなら、どの学科を勉強したいですか？その理由も書いてください。 (If you could go back to university, which department would you want to study in? Write the reason too.)

理科の授業で一番思い出に残っている実験は何ですか？ (What is the most memorable experiment from your science classes?)

自分の性格は、どの「科」に分類されると思いますか？ (What 'category' do you think your personality would be classified into?)

日本とあなたの国の病院の「科」の違いについて考えてみましょう。 (Think about the differences between 'departments' in Japanese hospitals and those in your country.)

Frequently Asked Questions

10 questions

科 (ka) is used for branches of science, medicine, and academic departments. For example, 'Internal Medicine' (内科) and 'Science' (理科). 課 (ka) is used for administrative sections in companies or government offices, like the 'Sales Section' (営業課) or 'First Section' (第一課). They are never interchangeable.

You should go to the 'Naika' (内科), which is the Internal Medicine department. This is the general department for non-surgical illnesses like the flu, stomach issues, or headaches. In Japan, this is the most common starting point for adult patients.

No. While 'Shika' (歯科) is the official name of the department/clinic, people often say 'Ha-isha' (歯医者) in casual conversation. However, the sign on the building will almost always say '歯科'.

'Gakka' (学科) means 'department'. A university is divided into 'Gakubu' (Faculties), and each Faculty has several 'Gakka'. For example, within the 'Faculty of Engineering' (工学部), you might find the 'Department of Mechanical Engineering' (機械工学科).

You say 'Rika' (理科). This is the standard term used in elementary and junior high schools. In high school, it becomes more specific, but 'Rika' is still the umbrella term for the science curriculum.

No, 'ka' refers to the department. To refer to the doctor, you add 'i' (doctor) to the specialty, like 'Gekai' (Surgeon) or 'Naikai' (Physician), or simply say '[Department] no sensei'.

It is the 'Obstetrics and Gynecology' department (産婦人科). It's a combination of 'San' (birth), 'Fu' (woman), 'Jin' (person), and 'Ka' (department). It is where women go for pregnancy and reproductive health.

It means the 'Felidae' or cat family in biology. Japanese uses the name of a representative animal followed by 'ka' to name biological families (e.g., Inu-ka for dogs/canines).

It literally means 'Hundred-Branch-Character-Book'. The 'Hyakka' (百科) part refers to many (hundred) branches of knowledge, showing the 'ka' suffix's role in categorization.

Yes, in daily life people say 'Jibika' (耳鼻科). The full formal name is 'Jibiinkouka' (耳鼻咽喉科 - Ear, Nose, and Throat department), but 'Jibika' is perfectly understood and very common.