Bisector

A ray which divides an angle into two congruent parts

If ray BF is an angle bisector, then m(a)CBF = m(a)FBA = 1/2m(a) CBA

A plane, point, line, ray or segment which divides a segment into two congruent parts. One of the segments formed by a segment bisector is equal in length to half the length of the original segment.