Meaning
The kanji 角 carries three core meanings: corner, angle, and horn. All three pivot on the same physical image — a sharp, pointed projection jutting out from a surface or body.
Etymologically, 角 is a pictograph. In its ancient oracle-bone form, the character depicted an animal horn — a curved, tapering shape rising from a skull. Over centuries of writing, that horn was squared off into the seven-stroke character used today. Look at the top strokes: the tapering tip is still there.
From that concrete image, the meaning spread naturally. A corner of a building or street is where two surfaces meet at a sharp junction — much like the base of a horn meets the skull. Geometry borrowed this kanji for angle for the same reason: both describe measured sharpness where two lines meet at a point.
角 has 7 strokes and is taught in Grade 2 of Japanese elementary school — early enough that children encounter it in math before they study formal geometry. It also serves as its own radical and appears as a component in 解 (to untie/solve) and 触 (to touch).
Readings
On'yomi (音読み) — Chinese-derived readings
The primary on'yomi is カク, from Middle Chinese. It dominates academic, scientific, and formal compounds — especially in geometry, anatomy, and abstract contexts.
- 角度 (kakudo) — angle, degree of inclination. Used extensively in mathematics and physics.
- 直角 (chokkaku) — right angle (90°). A fundamental term in geometry.
- 三角 (sankaku) — triangle; literally "three angles." Appears in 三角形 (triangle shape) and 三角関係 (love triangle).
- 四角 (shikaku) — square, rectangle; literally "four angles."
- 角膜 (kakumaku) — cornea of the eye. The Latin word cornea also means "horn-like" — the same etymology across languages.
- 頭角 (tōkaku) — prominence, standing out. From the image of horns rising above a herd.
- 一角 (ikkaku) — one corner, one aspect; also narwhal (一角獣).
Kun'yomi (訓読み) — Native Japanese readings
Two kun'yomi cover two distinct worlds: the built environment and living creatures.
かど (kado) refers to a corner or edge — typically a physical corner of a room, a building, a street intersection, or a box.
- 角 (kado) — corner, edge (standalone usage: "turn at the corner")
- 曲がり角 (magarikado) — a turning point; literally "a bending corner." Works both literally (a bend in a road) and figuratively (a turning point in life).
- 街角 (machikado) — street corner, a corner of town.
- 角張る (kadobaru) — to be angular, boxy, or stiff in manner. Used of both shapes and personalities.
つの (tsuno) is the horn or antler of an animal — the reading that connects directly to the kanji's pictographic origin.
- 角 (tsuno) — horn, antler (of a deer, ox, rhinoceros, etc.)
- 鬼の角 (oni no tsuno) — the horn of a demon (oni), a vivid image in Japanese folklore.
- 角砂糖 (kakuzatō) — sugar cube. This word uses the on'yomi カク and evokes the cube's angular shape.
Common Words & Compounds
角 turns up in geometry textbooks, apartment listings, and folklore alike. Key compounds by theme:
Geometry & Mathematics
- 角度 (kakudo) — angle, degree
- 直角 (chokkaku) — right angle
- 三角形 (sankakkei) — triangle
- 四角形 (shikakkei) — quadrilateral
- 多角形 (takakkei) — polygon; literally "many-angled shape"
- 鋭角 (eikaku) — acute angle
- 鈍角 (donkaku) — obtuse angle
Everyday Spatial Usage
- 角 (kado) — corner (of a room, street)
- 曲がり角 (magarikado) — road corner, turning point
- 街角 (machikado) — street corner
- 角部屋 (kadobeya) — corner room (room on the corner of a building)
- 角材 (kakuzai) — square timber; lumber with a rectangular cross-section
Nature & Body
- 角 (tsuno) — animal horn
- 角膜 (kakumaku) — cornea
- 頭角 (tōkaku) — prominence, standing out
Abstract & Figurative
- 一角 (ikkaku) — one aspect, one corner of a larger whole
- 角張った (kadobatta) — angular, stiff, formal (describing personality or shape)
Example Sentences
この道の角を右に曲がってください。
Kono michi no kado wo migi ni magatte kudasai.
Please turn right at the corner of this road.
三角形の内角の和は百八十度です。
Sankakkei no naikaku no wa wa hyakuhachijū-do desu.
The sum of the interior angles of a triangle is 180 degrees.
鹿の角はとても大きかった。
Shika no tsuno wa totemo ōkikatta.
The deer's antlers were very large.
机の角に頭をぶつけてしまった。
Tsukue no kado ni atama wo butsukete shimatta.
I accidentally bumped my head on the corner of the desk.
彼は若いころから頭角を現していた。
Kare wa wakai koro kara tōkaku wo arawashite ita.
He had been standing out since his youth.
この問題はさまざまな角度から考える必要がある。
Kono mondai wa samazama na kakudo kara kangaeru hitsuyō ga aru.
This problem needs to be considered from various angles.
角部屋は窓が多くて明るい。
Kadobeya wa mado ga ōkute akarui.
Corner rooms have many windows and are bright.
街角で古い友人に偶然会った。
Machikado de furui yūjin ni gūzen atta.
I unexpectedly ran into an old friend on a street corner.
直角三角形の斜辺が一番長い。
Chokkaku sankakkei no shahen ga ichiban nagai.
The hypotenuse of a right triangle is the longest side.
彼女の言葉は角が立っていて、みんなを不快にさせた。
Kanojo no kotoba wa kado ga tatte ite, minna wo fukai ni saseta.
Her words were sharp-edged and made everyone uncomfortable.
Memory Tip
Picture a unicorn's horn — pointed, angular, jutting boldly outward. 角 was literally drawn from an animal horn in ancient times. Now press that horn into the corner of a room: it fits perfectly into the 90-degree angle where two walls meet. One image, three meanings: horn (つの), corner (かど), and angle (カク). The top strokes even echo the tapering tip of a horn.