Circle

Semicircular region

Sector

Segment

Circumference

The collection of all the points in a plane, which are at a fixed distance from a fixed point in the plane

When two arcs are equal, that is, each is a semicircle, then both segments and both sectors become the same and each

The region between an arc and the two radii, joining the centre to the end points of the arc

The region between a chord and either of its arcs

The length of the complete circle