1. Having two sides or parts
   "The bilateral symmetry of a butterfly";
   - two-sided
    
2. Having identical parts on each side of an axis
   "The bilateral leaves of the plant were evenly distributed";
   - isobilateral, bilaterally symmetrical, bilaterally symmetric
    
3. Affecting or undertaken by two parties
   "a bilateral agreement between the United States and Japan"

See also: many-sided, multilateral, mutual, reciprocal, symmetric, symmetrical

Encyclopedia: Bilateral