pertaining to, involving, or affecting two or both sides, factions, parties, or the like

a bilateral agreement; bilateral sponsorship.

located on opposite sides of an axis; two-sided, esp. when of equal size, value, etc.

Biology . pertaining to the right and left sides of a structure, plane, etc.

Chiefly Law . (of a contract) binding the parties to reciprocal obligations.

through both parents equally

bilateral affiliation. Compare unilateral def. 7

Informal . a bilateral agreement, esp. regarding international trade.

adjective

multilateral , unilateral

adjective

mutual , reciprocal , respective , two-sided , binary , bipartisan , double , dual , duplicate , twin , twofold