Shikaku is the basic Japanese term for a four-sided shape or square-like object.
Word in 30 Seconds
- Refers to a shape with four sides and four angles.
- Commonly used as an adjective 'shikakui' for square-like objects.
- Fundamental geometry term for beginners.
Overview
- 1概要：四角は、幾何学において4つの直線で囲まれた図形を指します。日常的には、正方形や長方形など、角が直角である形を「四角」と呼ぶことが一般的です。2) 使用パターン：「四角い」という形容動詞として使われることが非常に多く、「四角い箱」「四角いテーブル」のように名詞を修飾します。また、名詞として「四角に切り取る」のように、特定の形を指す際にも用いられます。3) 一般的な文脈：日常生活で最も頻繁に使われます。身の回りの物の形を説明する際や、図形を描く際、あるいは料理の切り方を指示する際など、非常に幅広いシチュエーションで登場します。4) 類語との比較：「長方形」は縦と横の長さが異なる四角、「正方形」はすべての辺の長さが等しい四角を指します。「四角」はこれらを総称する、あるいは形が四角いことを大まかに表現する最も一般的な言葉です。
Examples
この箱は四角いです。
everydayThis box is square.
四角いテーブルを囲んで会議をしました。
formalWe held a meeting around the square table.
四角に切ってください。
informalPlease cut it into a square shape.
四角形の内角の和は360度です。
academicThe sum of the interior angles of a quadrilateral is 360 degrees.
Common Collocations
Common Phrases
四角四面
Stiff, formal, or overly serious
四角い頭
Narrow-minded or stubborn
Often Confused With
Refers specifically to a rectangle. Use this when the length and width are clearly different.
Refers specifically to a square. Use this when all four sides are exactly the same length.
Grammar Patterns
How to Use It
Usage Notes
Use 'shikaku' as a noun for the shape itself and 'shikakui' as an adjective to describe objects. It is a very neutral and common word. Avoid using it in highly technical mathematical contexts where 'shikakukei' (quadrilateral) is required.
Common Mistakes
Learners often confuse 'shikaku' and 'shikakui'. Remember that 'shikaku' is the noun (the shape) and 'shikakui' is the adjective (the property). Using 'shikaku' to modify a noun directly is grammatically incorrect.
Tips
Use Shikakui for descriptions
When describing objects like boxes or rooms, use the adjective form 'shikakui'. It is the most natural way to describe square or rectangular shapes in daily life.
Difference from Square
Be careful that 'shikaku' is not always a perfect square. Use 'seihoukei' if you strictly mean a square with four equal sides.
Cultural preference for shapes
In Japan, the concept of 'shikaku' is often associated with traditional items like 'shikishi' (square paper for calligraphy) or 'jubako' (square food boxes).
Word Origin
Derived from the kanji '四' (four) and '角' (corner). It literally means 'four corners', which perfectly describes its geometric property.
Cultural Context
In Japan, the square shape is often preferred for efficiency in packaging and architecture. You will see many 'shikakui' items in Japanese convenience stores and homes.
Memory Tip
Think of a 'shi' (four) 'kaku' (corner) object. If it has four corners, it's a shikaku!
Frequently Asked Questions
4 questions「正方形」は4つの辺がすべて等しい図形という厳密な定義ですが、「四角」は形が四角いもの全般を指す広い意味の言葉です。日常会話では、長方形であっても「四角い」と呼ぶことが一般的です。
はい、「四角い」という形で形容動詞として使います。例えば「四角い部屋」のように名詞を修飾して使います。
数学では「四角形」という言葉が正式ですが、日常会話では「四角」が使われます。数学のテストなどで図形を指す場合は「四角形」を使うのが適切です。
はい、「四角い頭」は頭が固い、融通が利かないという意味の比喩表現として使われることがあります。ただし、少し古い言い方かもしれません。
Test Yourself
このテーブルは___形をしています。
名詞を修飾するため、形容動詞の「四角い」が適切です。
「四角」について正しいものはどれですか？
四角は4つの角と辺を持つ図形を指します。
（四角い / 買いました / 箱を / 私は）
「主語＋修飾語＋目的語＋動詞」の語順が自然です。
Score: /3
Summary
Shikaku is the basic Japanese term for a four-sided shape or square-like object.
- Refers to a shape with four sides and four angles.
- Commonly used as an adjective 'shikakui' for square-like objects.
- Fundamental geometry term for beginners.
Use Shikakui for descriptions
When describing objects like boxes or rooms, use the adjective form 'shikakui'. It is the most natural way to describe square or rectangular shapes in daily life.
Difference from Square
Be careful that 'shikaku' is not always a perfect square. Use 'seihoukei' if you strictly mean a square with four equal sides.
Cultural preference for shapes
In Japan, the concept of 'shikaku' is often associated with traditional items like 'shikishi' (square paper for calligraphy) or 'jubako' (square food boxes).
Examples
4 of 4この箱は四角いです。
This box is square.
四角いテーブルを囲んで会議をしました。
We held a meeting around the square table.
四角に切ってください。
Please cut it into a square shape.
四角形の内角の和は360度です。
The sum of the interior angles of a quadrilateral is 360 degrees.
Related Content
This Word in Other Languages
More general words
能力
A1Nouryoku refers to the mental or physical power, skill, or capacity required to perform a specific task or function. It can describe both innate talent and skills acquired through learning and practice.
異常
A1A word used to describe something that deviates from the normal state, standard, or expected pattern. It often implies a problem, malfunction, or an extraordinary occurrence that requires attention or investigation.
～について
A2About, concerning; indicates topic.
〜について
B1About, concerning; on the subject of.
～ぐらい
A2about, approximately
ぐらい
A2About; approximately; to the extent of.
ごろ
A2About, approximately (time).
うえ
A2At a higher position than.
絶対
B1Absolutely; definitely; never.
絶対に
B1Absolutely; definitely.
