Sector. In Geometry, is a portion of a circle included between two radii and the intercepted arc of the circumference. The area of a sector is equal to that of a triangle whose base is equal in length to the intercepted arc, and whose perpendicular height is equal to the length of the radius.
Sector.
Chambers's Encyclopaedia, Volume 9: Bound to Swansea, p. 296
Source scan(s): p. 0309