鋭角(えいかく)

えいかく
noun
acute angle
1. acute angle
An angle measuring less than 90 degrees.
鋭角(えいかく)は90度(ど)未満(みまん)の角(かく)だ。
An acute angle is an angle less than 90 degrees.
この三角形(さんかくけい)は全(すべ)ての角(かく)が鋭角(えいかく)だ。
All angles in this triangle are acute angles.
45度(ど)は鋭角(えいかく)の一例(いちれい)だ。
45 degrees is an example of an acute angle.

鋭角(えいかく) is a mathematical term for an angle less than 90 degrees. The kanji 鋭(えい) means 'sharp,' reflecting the pointed appearance of small angles.

ANGLE TYPES:

  • 鋭角(えいかく): acute angle (0° < θ < 90°)
  • 直角(ちょっかく): right angle (θ = 90°)
  • 鈍角(どんかく): obtuse angle (90° < θ < 180°)
  • 平角(へいかく): straight angle (θ = 180°)

RELATED TERMS:

  • 鋭角(えいかく)三角形(さんかくけい): acute triangle (all angles acute)
  • 角度(かくど): angle (measurement)
  • 三角形(さんかくけい): triangle

FIGURATIVE USE:
鋭角(えいかく)的(てき) (adjective) can describe something sharp or incisive, as in 鋭角(えいかく)的(てき)な視点(してん) (a sharp perspective).

Related Words

Antonym: 鈍角(どんかく) (obtuse angle)
Antonym: 直角(ちょっかく) (right angle)
general
Added 2026.1.16 17:09 · Revised 2026.4.14 15:33
05500/05554_eikaku