CIRCLE AND ITS RELATED TERMS

Circle is the set of all points in a plane that are equidistant from a given point in the plane known as the center of the circle.

Chord - is a segment whose endpoints lie on a circle

Secant - is a line that intersects the circle at two points

Diameter is the longest secant in a circle.

Tangent - is a line in the plane of the circle that intersects the circle at exactly one point 

Sector -The part of a circle enclosed by two radii  of a circle and an arc.

The cut piece of pizza is minor sector and the remaining is the major sector.

Segment -part of a circle bounded by a chord and an arc

Semi-circle - is an arc whose endpoints are endpoints of a diameter