Either of the two arcs of a circle intersected by a diameter of the circle. A semicircle is named by three points, its endpoints and a third point on the semicircle.

a unit of angle measurement equal to 1/2 circle, pi radians, or 180°.

a figure contained by the diameter and the circumference cut off by it. And the center is the same as that of the circle.

a plane figure with the shape of half a circle

a figure contained by a diameter the part of the circumference cut off by it

Half a circle; either of the two parts of a circle cut off by a diameter.

(2) Half of a circle; either of two parts of a circle between (and including) the endpoints of a diameter.

An arc of a circle whose endpoints are the endpoints of a diameter (Lesson 7.1).

In mathematics (more specifically geometry), a semicircle is a two-dimensional geometric shape that forms half of a circle. Being half of a circle's 360Â°, the arc of a semicircle always measures 180Â°. Additionally, an angle in a semicircle is always a right angle.