a. [ Pref. bi- + lateral: cf. F. bilatéral. ] 1. Having two sides; arranged upon two sides; affecting two sides or two parties. [ 1913 Webster ]
2. (Biol.) Of or pertaining to the two sides of a central area or organ, or of a central axis; as, bilateral symmetry in animals, where there is a similarity of parts on the right and left sides of the body. [ 1913 Webster ]