Bilateral \Bi*lat"er*al\, a. [Pref. bi- + lateral: cf. F. bilat['e]ral.]

1. Having two sides; arranged upon two sides; affecting two sides or two parties.

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.

Source: Webster's Revised Unabridged Dictionary (1913)