- adjective involving two groups of people.
- Between two countries, in contrast to plurilateral and multilateral.
- Having two sides. Also, that which pertains to, or affects these sides in an equal manner. Bilateral and bidirectional may be contrasted in the following manner: bilateral refers to the two sides of something, while bidirectional pertains to two directions. Though not necessarily the same, these terms are sometimes used synonymously.
- adjective affecting both sides