On the circle we distinguish two fundamental objects: the portion of curve between two points (the arc) and the segment that joins them (the chord).

Definition — Arc and chord

An arc is the portion of the circle between two points AA and BB. Two points determine two arcs: the minor arc and the major arc.

A chord is the segment joining two points of the circle. The chord ABAB is said to subtend the arc ABAB (by convention, the minor one).

Topics: Euclidean circle
Concepts: Arc · Chord