半径(はんけい)

はんけい
noun
radius
1. radius
The distance from the center of a circle to its edge; also used to describe the area within a certain distance from a point.
円(えん)の半径(はんけい)は5センチです。
The radius of the circle is 5 centimeters.
駅(えき)から半径(はんけい)1キロ以内(いない)にコンビニがある。
There's a convenience store within a 1 km radius of the station.
車(くるま)を買(か)ってから行動(こうどう)半径(はんけい)が広(ひろ)がった。
Since buying a car, my range of activities has expanded.

USAGE: 半径(はんけい) is used both in mathematics (geometry) and in everyday contexts to describe the area within a certain distance from a center point.

COMMON PATTERNS:

MATHEMATICS:

NOTE: 行動(こうどう)半径(はんけい) (action radius) is a common figurative usage meaning the scope or range of one's activities.

Related Words

Related: 直径(ちょっけい) (diameter)
general
Added 2026.1.14 9:58 · Revised 2026.5.31 6:10
04000/04331_hankei