Circular segment

A circular segment (in green) is enclosed between a secant/chord (the dashed line) and the arc whose endpoints equal the chord's (the arc shown above the green area).

In geometry, a circular segment or disk segment (symbol: ⌓) is a region of a disk[1] which is "cut off" from the rest of the disk by a straight line. The complete line is known as a secant, and the section inside the disk as a chord.[2]

More formally, a circular segment is a plane region bounded by a circular arc (of less than π radians by convention) and the circular chord connecting its endpoints.

  1. ^ Mathematics distinguishes when necessary between the words circle and disk: a disk is a plane area having a circle as its boundary, while a circle is the closed curve forming the boundary itself.
  2. ^ These terms refer to a line which intersects a curve. In this case, the curve is the circle forming the disk's boundary.