At the A1 level, you don't need to know the deep physics of '陽子' (yōshi). However, you might see it in a very basic science book or as a name. In Japanese, '陽子' can be a girl's name read as 'Yōko'. If you see it in a list of names, it's 'Yōko'. If you see it in a picture of an atom (a small circle with a plus sign), it's 'yōshi' (proton). Just remember that 'yō' means 'sun' or 'plus' and 'shi' means 'small thing'. It is a very specific word for science class. You probably won't use it when ordering food or meeting friends, but it's a cool word to know if you like science! At this stage, just recognize the kanji and know it relates to science or is a common name.
At the A2 level, you are starting to learn more specific nouns. '陽子' (yōshi) is the word for 'proton'. You might hear this in a basic Japanese news report about science or see it in a high school textbook. It is important to know that it is part of a group: 陽子 (proton), 電子 (electron), and 中性子 (neutron). They all end with '子' (shi), which means 'particle' in this context. You can use it in simple sentences like 'The atom has protons.' (原子には陽子があります). Also, remember the difference between the reading 'yōshi' (science) and 'Yōko' (name). If you are talking about science, always say 'yōshi'. This will help you sound more accurate when discussing school subjects or basic technology.
At the B1 level, you should be able to understand '陽子' (yōshi) in the context of general science articles or educational videos. You should know that 陽子 has a positive charge (プラスの電荷). You might encounter this word when reading about how the universe began or how nuclear power works. It's often used with the particle 'から成る' (kara naru - to consist of). For example, 'The nucleus consists of protons and neutrons' (原子核は陽子と中性子から成っています). You should also be aware of the term '陽子線治療' (yōshisen chiryō - proton beam therapy), as health and technology are common B1 topics. Understanding this word helps you bridge the gap between daily Japanese and academic Japanese.
At the B2 level, you are expected to understand '陽子' (yōshi) in more complex scientific discussions. You should be familiar with its properties, such as its mass and how it determines the atomic number (原子番号). You will see it in phrases like '陽子の衝突' (proton collision) or '陽子の崩壊' (proton decay). At this level, you should also be able to explain the word using other Japanese words, such as '原子核を構成する、プラスの電気を持った粒子です' (It is a positively charged particle that makes up the atomic nucleus). You might also see it in science fiction literature or more detailed news reports about research at facilities like J-PARC or CERN. Your ability to use technical terms like this correctly shows a high level of literacy.
At the C1 level, '陽子' (yōshi) is a word you should be able to use fluently in academic or professional scientific contexts. You should understand the nuances of its role in quantum mechanics and nuclear physics. For instance, you might discuss the '陽子の内部構造' (internal structure of the proton) involving quarks and gluons. You should also be comfortable with related high-level terminology like '陽子線' (proton beam) in the context of oncology or '陽子・陽子連鎖反応' (proton-proton chain reaction) in astrophysics. At this level, you are not just recognizing the word, but understanding its implications in complex systems and being able to debate or present on topics involving subatomic physics in Japanese.
At the C2 level, your mastery of '陽子' (yōshi) is equivalent to that of a native specialist. You can engage in deep theoretical discussions about the stability of the proton, the '陽子半径パズル' (proton radius puzzle), and the fundamental symmetries of the universe. You understand the historical development of the term in Japanese science and can read original research papers in Japanese that use this terminology. You can distinguish between subtle uses of the word in various fields, from particle physics to medical radiology. For a C2 learner, '陽子' is a fundamental building block of a vast technical vocabulary that allows for precise, sophisticated communication in the highest levels of Japanese academia and industry.

陽子 30초 만에

  • 陽子 (yōshi) means 'proton', a positively charged particle in an atom's nucleus. It is a fundamental term in chemistry and physics.
  • The kanji 陽 (positive/sun) and 子 (particle) literally describe its nature as a 'positive particle', making it easy to identify.
  • It is commonly used in science education, news about particle physics, and specialized medical contexts like 'proton beam therapy'.
  • Avoid reading it as 'Yōko' (a female name) in scientific contexts; the correct technical reading is always 'yōshi'.

The Japanese word 陽子 (ようし - yōshi) is a technical scientific term that translates directly to 'proton' in English. To understand this word, we must look at its constituent kanji characters, which provide a beautiful logic to its meaning. The first character, 陽 (yō), represents the 'yang' in the yin-yang duality, often associated with the sun, light, and importantly in a scientific context, a positive charge. The second character, 子 (shi), is a common suffix used for small objects, children, or in physics, particles. Therefore, 陽子 literally translates to 'positive particle.'

Scientific Classification
Subatomic particle (素粒子 - soryūshi) found in the atomic nucleus.
Charge
Positive electric charge (+1e).
Role
Determines the atomic number and chemical identity of an element.

水素の原子核は、通常一つの陽子だけで構成されています。(The nucleus of a hydrogen atom usually consists of just one proton.)

In the broader context of Japanese vocabulary, 陽子 belongs to a family of 'particle' words ending in 子. You will often see it paired with 中性子 (chūseishi - neutron) and 電子 (denshi - electron). Together, these three form the basic building blocks of matter as taught in Japanese middle school and high school science curricula. While the word is technical, it is essential for anyone reading scientific literature, watching educational programs like NHK's science specials, or discussing chemistry and physics in Japanese.

原子の重さは、主に陽子と中性子の数で決まります。(The weight of an atom is mainly determined by the number of protons and neutrons.)

From a linguistic perspective, the use of 陽 (positive) highlights the Japanese approach to scientific nomenclature, which often uses descriptive kanji to mirror Western concepts. Just as 'proton' comes from the Greek 'protos' (first), the Japanese term focuses on the fundamental 'positive' nature of the particle. This makes the word relatively easy to remember once you associate 陽 with positivity and light.

陽子の数は原子番号と同じです。(The number of protons is the same as the atomic number.)

Mass Comparison
Approximately 1,836 times heavier than an electron.
Stability
Considered a stable particle with an extremely long half-life.

加速器を使って陽子を衝突させる実験が行われました。(An experiment was conducted using an accelerator to collide protons.)

Using 陽子 (yōshi) correctly requires an understanding of its specific domain: science and medicine. Unlike general vocabulary, you won't use 陽子 in casual conversation unless you are discussing a science project, a documentary, or a medical treatment. It is a noun that functions as a subject or object in a sentence, often followed by particles like は (wa), が (ga), or を (o).

When discussing atomic structure, 陽子 is almost always mentioned alongside its counterparts. For example, 'The nucleus contains protons and neutrons' becomes 原子核には陽子と中性子が含まれています. Notice how the particle と (to - and) is used to link these technical terms. In academic writing, you will see 陽子 combined with other nouns to create compound terms. Common examples include 陽子数 (yōshisū - number of protons) and 陽子崩壊 (yōshi hōkai - proton decay).

ヘリウムの原子核には二つの陽子があります。(There are two protons in the nucleus of helium.)

In medical contexts, particularly regarding cancer treatment, you will encounter 陽子線 (yōshisen - proton beam). This is a highly specialized use of the word. A sentence might look like: 彼は陽子線治療を受けています (He is undergoing proton beam therapy). Here, 陽子 describes the type of radiation being used. It is important to maintain the formal reading yōshi here; using the name reading yōko would make the sentence nonsensical or even humorous in a professional setting.

Grammar Tip
陽子 is a countable noun in physics, often used with counters like 個 (ko) or つ (tsu).
Formal vs. Informal
The word itself is inherently formal/technical. There is no 'casual' version of proton.

If you are a student of Japanese, you might encounter this word in the JLPT N1 or N2 level reading passages related to science or technology. It is also a staple of the EJU (Examination for Japanese University Admission) science sections. When writing about 陽子, ensure that your kanji for is correct—it is the same 'yō' as in 太陽 (taiyō - sun), which helps reinforce the idea of 'positive energy' or 'light'.

この研究は陽子の内部構造を解明することを目的としています。(This research aims to clarify the internal structure of the proton.)

You will encounter 陽子 (yōshi) in several specific environments. The most common is the Japanese classroom. From junior high school onwards, students learn about the periodic table and atomic structure. A teacher might say, 「原子の真ん中には、陽子と中性子があります」 (In the center of the atom, there are protons and neutrons). This is the foundational context for most native speakers.

Another major source is science documentaries and news reports. Japan has a strong interest in particle physics, partly due to its numerous Nobel Prize winners in the field (like Hideki Yukawa or Makoto Kobayashi). When a new discovery is made at the Super-Kamiokande or CERN, news anchors will frequently use terms like 陽子衝突 (yōshi shōtotsu - proton collision). Listening for these terms in NHK News is a great way to hear the word used in a natural, high-register context.

科学ニュースで陽子の寿命についての新しい説が発表されました。(A new theory about the lifespan of a proton was announced on the science news.)

In the medical field, specifically in hospitals that offer advanced cancer care, you will hear 陽子線治療 (yōshisen chiryō). Patients and doctors discuss this as a targeted form of radiation. It is often contrasted with X-ray therapy because of its precision. Hearing this word in a hospital setting indicates a discussion about cutting-edge technology and specialized care.

Media Source
Newton Magazine (Japanese science monthly).
Pop Culture
Science fiction anime like 'Steins;Gate' or 'Neon Genesis Evangelion' often use particle physics terminology.

Finally, you might hear it in university lectures. If you are auditing a physics or chemistry course in Japan, 陽子 will be a high-frequency word. Professors will use it while drawing diagrams on the board, often abbreviating it as 'p' (from the English 'proton') but referring to it verbally as yōshi. Understanding this word allows you to follow the logical flow of scientific arguments in Japanese academic settings.

The most frequent mistake learners make with 陽子 is confusing its reading. Because the kanji combination 陽子 is a very common female given name, many students instinctively read it as Yōko. While 'Yōko' is a perfectly valid name, it never means 'proton'. In a scientific context, you must use the 'on-yomi' reading yōshi. If you say 'Yōko' in a chemistry lab, people will think you are calling out to a colleague named Yoko rather than discussing subatomic particles.

Another mistake is confusing 陽子 with 電子 (denshi - electron) or 中性子 (chūseishi - neutron). Since they all end in 'shi' (子), it is easy to mix them up. Remember: 陽 (yō) means positive/sun, 中性 (chūsei) means neutral, and 電 (den) means electricity (associated with the negative flow in this context). Associating the first kanji with the charge is the best way to avoid this error.

❌ 電子はプラスの電荷を持っています。(Electrons have a positive charge.)
陽子はプラスの電荷を持っています。(Protons have a positive charge.)

Grammatically, some learners forget that 陽子 is a noun and try to use it as an adjective without the proper particles. You cannot say 'yōshi structure'; you must say 陽子の構造 (yōshi no kōzō) or use the compound 陽子構造 (yōshi kōzō). Additionally, ensure you don't confuse 陽子 (proton) with 陽イオン (yō-ion - positive ion/cation). While both are positive, a proton is a single particle, whereas a cation is an entire atom or molecule that has lost electrons.

Mistake 1
Reading it as 'Yōko' in a science context.
Mistake 2
Confusing it with 電子 (electron) or 中性子 (neutron).
Mistake 3
Confusing it with 陽イオン (cation).

To truly master 陽子 (yōshi), it is helpful to understand its 'family' of related scientific terms. The most immediate relatives are the other subatomic particles. 中性子 (chūseishi) is the neutron. The 'chūsei' part means 'neutrality,' which is easy to remember because neutrons have no charge. Then there is 電子 (denshi), the electron. 'Den' means electricity, reflecting the electron's role in electrical currents.

Beyond these, we have 原子核 (genshikaku), which means 'atomic nucleus.' The 陽子 and 中性子 live inside the 原子核. If you are talking about the smallest possible particles, you use the term 素粒子 (soryūshi), meaning 'elementary particle.' Protons were once thought to be elementary, but we now know they are made of クォーク (kuōku - quarks).

陽電子 (yōdenshi)
Positron (the antimatter counterpart of an electron). Don't confuse this with a proton!
原子 (genshi)
Atom. The whole structure containing protons, neutrons, and electrons.
分子 (bunshi)
Molecule. A group of atoms bonded together.

陽子と中性子は、強い相互作用によって原子核の中に留まっています。(Protons and neutrons stay inside the nucleus due to the strong interaction.)

Another similar-sounding but different word is 様子 (yōsu). While it also ends in 'su/shi' and starts with 'yō', it means 'appearance' or 'state of affairs.' This is a very common daily word. 「外の様子を見てきて」 (Go check the situation outside). Be careful not to let the scientific yōshi and the daily yōsu get tangled in your mind. Finally, 粒子 (ryūshi) is the general term for 'particle' or 'grain,' which 陽子 is a specific type of.

How Formal Is It?

난이도

알아야 할 문법

Noun + について (About...)

A は B から成る (A consists of B)

Passive voice for scientific facts

Counters for particles (個)

Compound noun formation

수준별 예문

1

これは陽子です。

This is a proton.

Simple A is B structure.

2

陽子は小さいです。

Protons are small.

Adjective usage.

3

陽子の色は赤ですか?

Is the color of the proton red?

Possessive 'no'.

4

ここに陽子があります。

There is a proton here.

Existence verb 'arimasu'.

5

陽子を一つ書きます。

I will draw one proton.

Object marker 'o' and counter.

6

陽子はプラスです。

Protons are positive.

Noun as a predicate.

7

理科の本に陽子がありました。

There was a 'proton' in the science book.

Past tense of 'arimasu'.

8

陽子と電子を見ます。

I see a proton and an electron.

Connecting nouns with 'to'.

1

原子の中には陽子があります。

There are protons inside the atom.

Locational particle 'naka ni'.

2

陽子の数は大切です。

The number of protons is important.

Noun phrase as subject.

3

水素は陽子が一つだけです。

Hydrogen has only one proton.

Limiting particle 'dake'.

4

先生が陽子について教えました。

The teacher taught about protons.

Topic marker 'nitsuite'.

5

陽子と中性子は核にあります。

Protons and neutrons are in the nucleus.

Compound subject.

6

陽子は電子より重いです。

Protons are heavier than electrons.

Comparison 'yori'.

7

この図は陽子を表しています。

This diagram represents a proton.

Verb 'arawasu' (represent).

8

陽子の電気はプラスです。

The electricity of a proton is positive.

Possessive description.

1

陽子の数によって原子番号が決まります。

The atomic number is determined by the number of protons.

Passive form 'kimarimasu' and 'ni yotte'.

2

陽子線治療はがんの治療に使われます。

Proton beam therapy is used for cancer treatment.

Passive 'tsukawaremasu'.

3

原子核は陽子と中性子から構成されています。

The atomic nucleus is composed of protons and neutrons.

Compound verb 'kōsei sarete iru'.

4

陽子はプラスの電荷を持っています。

Protons possess a positive electric charge.

Verb 'motsu' (to hold/possess).

5

科学者は陽子の性質を研究しています。

Scientists are researching the properties of protons.

Continuous form 'shite imasu'.

6

陽子がなければ、原子は存在しません。

Without protons, atoms would not exist.

Conditional 'nakereba'.

7

この実験では陽子を加速させます。

In this experiment, protons are accelerated.

Causative form 'kasoku sasemasu'.

8

陽子の重さは中性子とほぼ同じです。

The weight of a proton is almost the same as a neutron.

Adverb 'hobo' (almost).

1

陽子の内部には三つのクォークが存在します。

There are three quarks inside a proton.

Existential verb 'sonzai suru'.

2

陽子崩壊はまだ観測されていません。

Proton decay has not been observed yet.

Present perfect negative passive.

3

陽子と陽子の衝突により、新しい粒子が生まれます。

New particles are born from the collision of protons.

Causal 'ni yori'.

4

この加速器は陽子を光速近くまで加速できます。

This accelerator can speed up protons to near the speed of light.

Potential form 'kasoku dekiru'.

5

陽子のスピンは1/2という値を持っています。

The spin of a proton has a value of 1/2.

Apposition 'to iu'.

6

陽子線は周囲の組織へのダメージを抑えることができます。

Proton beams can minimize damage to surrounding tissue.

Verb 'osaeru' (suppress/minimize).

7

原子の化学的性質は陽子の数で定義されます。

The chemical properties of an atom are defined by the number of protons.

Passive 'teigi saremasu'.

8

陽子の質量は電子の約1836倍です。

The mass of a proton is about 1836 times that of an electron.

Multiplier 'bai'.

1

陽子の電荷半径に関する測定結果が議論を呼んでいます。

Measurement results regarding the proton's charge radius are sparking debate.

Compound noun phrase 'ni kansuru'.

2

強い相互作用が陽子と中性子を原子核内に束縛しています。

The strong interaction binds protons and neutrons within the nucleus.

Technical verb 'sokubaku suru'.

3

陽子の寿命は宇宙の年齢よりもはるかに長いと考えられています。

The lifespan of a proton is thought to be much longer than the age of the universe.

Passive conjecture 'to kangaerarete iru'.

4

高エネルギー物理学において、陽子は重要な役割を果たします。

In high-energy physics, protons play a crucial role.

Idiom 'yakuwari o hatasu'.

5

陽子ビームのエネルギー分布を精密に制御する必要があります。

It is necessary to precisely control the energy distribution of the proton beam.

Necessity 'hitsuyō ga aru'.

6

この論文は陽子の構造関数についての新しい知見を提供しています。

This paper provides new insights into the structure function of the proton.

Noun 'chiken' (insight/knowledge).

7

陽子散乱実験により、原子核の密度分布が明らかになりました。

Proton scattering experiments clarified the density distribution of the nucleus.

Resultative 'akiraka ni narimashita'.

8

標準模型によれば、陽子は安定した粒子とされています。

According to the Standard Model, the proton is considered a stable particle.

Source marker 'ni yoreba'.

1

陽子の内部におけるグルーオンの寄与を定量的に評価する。

Quantitatively evaluate the contribution of gluons within the proton.

Formal 'suru' ending for research.

2

格子量子色力学を用いた陽子質量の計算精度が向上している。

The accuracy of proton mass calculations using lattice QCD is improving.

Technical compound 'kōshi ryōshi shikirikigaku'.

3

陽子のスピン危機の解決に向けた実験的アプローチが模索されている。

Experimental approaches toward resolving the proton spin crisis are being explored.

Passive 'mosaku sarete iru'.

4

パリティ対称性の破れを検証するため、偏極陽子衝突が利用される。

Polarized proton collisions are used to verify parity symmetry breaking.

Purpose 'tame' and technical term 'henkyoku'.

5

陽子半径パズルの解決は、現代物理学の最優先課題の一つである。

Solving the proton radius puzzle is one of the top priorities of modern physics.

Superlative 'saiyūsen'.

6

深非弾性散乱実験を通じて、陽子のパートン構造が解明された。

The parton structure of the proton was elucidated through deep inelastic scattering experiments.

Through/via 'tsūjite'.

7

陽子の磁気モーメントの異常値は、未知の物理現象を示唆している可能性がある。

Anomalies in the proton's magnetic moment may suggest unknown physical phenomena.

Possibility 'kanōsei ga aru'.

8

大統一理論の検証において、陽子崩壊の探索は不可欠な要素である。

In the verification of Grand Unified Theories, the search for proton decay is an indispensable element.

Indispensable 'fukaketsu'.

동의어

プロトン 正電荷粒子 バリオン 重粒子

반의어

電子 反陽子

자주 쓰는 조합

陽子の数 (number of protons)
陽子線治療 (proton beam therapy)
陽子崩壊 (proton decay)
陽子衝突 (proton collision)
陽子加速器 (proton accelerator)
陽子の質量 (mass of a proton)
陽子のスピン (proton spin)
陽子の半径 (proton radius)
陽子放出 (proton emission)
陽子交換膜 (proton exchange membrane)

자주 혼동되는 단어

陽子 vs 陽子 (Yōko - name)

陽子 vs 様子 (yōsu - state/appearance)

陽子 vs 養子 (yōshi - adopted child)

혼동하기 쉬운

陽子 vs 養子

陽子 vs 様子

陽子 vs 陽電子

陽子 vs 電子

陽子 vs 中性子

문장 패턴

어휘 가족

관련

太陽 (taiyō)
陽気 (yōki)
陽光 (yōkō)
陽極 (yōkyoku)
陽性 (yōsei)

사용법

personal

Read as Yōko when it's a name.

scientific

Always read as yōshi.

자주 하는 실수
  • Reading as Yōko in science class.
  • Confusing with 電子 (electron).
  • Writing 湯子 instead of 陽子.
  • Thinking 陽子 is an ion.
  • Using 'yōshi' to mean 'appearance'.

Kanji Logic

Remember 陽 is for 'positive' and 子 is for 'particle'. Together they make 'positive particle'.

Long Vowel

Make sure to stretch the 'yo' sound. It is yōshi, not yoshi.

Science vs Name

If you see it in a textbook, it's a proton. If it's on a business card, it's Yoko.

The Trio

Always learn 陽子, 電子, and 中性子 together as a set.

Radical Check

The left side of 陽 is the 'hill' radical (阝), representing the sunny side of a hill.

Medical Use

If you hear 'yōshisen', it almost always refers to cancer treatment.

JLPT Prep

This word appears in N1/N2 level science-related reading passages.

NHK Science

Watch NHK science programs to hear this word used by experts.

Counters

Use 'ko' (個) to count protons in an atom.

Mass Tip

Protons and Neutrons are heavy; Electrons are light. Remember this for context.

암기하기

어원

Translation of the Western term 'proton' using Sino-Japanese characters during the Meiji era modernization.

문화적 맥락

陽子 (Yōko) is a classic 'ko' name, often chosen for its bright, positive meaning.

Science literacy is a point of national pride in Japan.

실생활에서 연습하기

실제 사용 상황

대화 시작하기

"陽子線治療について聞いたことがありますか?"

"原子の構造で陽子の役割は何ですか?"

"日本の物理学者が陽子の研究で有名ですね。"

"陽子と電子、どちらが重いか知っていますか?"

"「陽子」という名前の知り合いはいますか?"

일기 주제

今日学んだ陽子の性質について日本語で書いてみましょう。

もし科学者だったら、陽子の何を研究したいですか?

陽子線治療のメリットについて調べて書きましょう。

「陽子」という漢字から受ける印象を記述してください。

原子の不思議について日本語で日記を書きましょう。

자주 묻는 질문

10 질문

文脈によります。科学なら「ようし」(proton)、名前なら「ようこ」です。

原子の中心にある原子核の中にあります。

プラス(正)の電荷を持っています。

陽子の束を使ってがん細胞を狙い撃ちする高度な放射線治療です。

電子の約1836倍の重さがあります。

現在の物理学では、陽子は非常に安定しており、寿命は極めて長いとされています。

原子番号に関係し、その原子がどの元素であるかを決定します。

クォークと呼ばれるさらに小さな粒子が3つ入っています。

アーネスト・ラザフォードが発見したとされています。

太陽や、明るいこと、プラス(正)であることを意味します。

셀프 테스트 180 질문

/ 180 correct

Perfect score!

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