English

incircle

From in- + circle.

A compound of in- + circle

Proto-Indo-European *h₁én ‘in’

Proto-Germanic *in ‘into’

English in-

Latin circus ‘circle’

Latin circulus

Old French cercle ‘circle’

Middle English circle

Today it means

noun A circle within a polygon, especially a triangle, that is tangent to each side.

Language periods are conventional ranges, not dates for this word.

Etymograph / incircle