線分(せんぶん)

せんぶん
noun
line segment
science
1. line segment
In geometry, the portion of a line between two endpoints. Unlike a line, which extends infinitely in both directions, a line segment has a definite length.
線分(せんぶん)ABの長(なが)さを求(もと)めなさい。
Find the length of line segment AB.
二点(にてん)を結(むす)ぶ線分(せんぶん)を引(ひ)いた。
I drew a line segment connecting two points.
三角形(さんかっけい)の各辺(かくへん)は線分(せんぶん)であり、その長(なが)さの合計(ごうけい)が周(しゅう)の長(なが)さになる。
Each side of a triangle is a line segment, and the sum of their lengths is the perimeter.

Composed of 線(せん) (line) and 分(ぶん) (part, segment). A fundamental geometry term taught in elementary and middle school mathematics. The concept distinguishes a bounded portion of a line (with two endpoints) from a full 直線(ちょくせん) (line, extending infinitely) or a 半直線(はんちょくせん) (ray, extending infinitely in one direction).

Common collocations

  • 線分(せんぶん)の長(なが)さ: length of a line segment
  • 線分(せんぶん)の中点(ちゅうてん): midpoint of a line segment
  • 線分(せんぶん)を引(ひ)く: to draw a line segment
  • 線分(せんぶん)ABを二等分(にとうぶん)する: to bisect line segment AB

Related words

  • 直線(ちょくせん): straight line — extends infinitely in both directions
  • 半直線(はんちょくせん): ray — has one endpoint, extends infinitely in one direction
  • 辺(へん): side (of a polygon) — a line segment forming part of a shape

Related Words

Related: 直線(ちょくせん) (straight line)
Related: 辺(へん) (side)
general
Added 2026.5.1 1:26 · Revised 2026.9.2 13:02
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