D defs.my
Entry 1 sense Webster, 1913

Bisector

/bī'sĕktər/ · Bi·sec·tor · IPA /ˈbaɪˌsɛktɚ/
01 n. One who, or that which, bisects; esp. (Geom.) a straight line which bisects an angle.
  1. 1.
    One who, or that which, bisects; esp. (Geom.) a straight line which bisects an angle.(Geom.)