Definify.com
Webster 1913 Edition
Semicircle
Sem′i-cirˊcle
,Noun.
1.
(a)
The half of a circle; the part of a circle bounded by its diameter and half of its circumference.
(b)
A semicircumference.
2.
A body in the form of half of a circle, or half of a circumference.
3.
An instrument for measuring angles.
Webster 1828 Edition
Semicircle
SEM'ICIRCLE
,Noun.
1. The half of a circle; the part of a circle comprehended between its diameter and half of its circumference.
2. Any body in the form of a half circle.