relating to, occurring on, or involving one side only

unilateral development; a unilateral approach.

undertaken or done by or on behalf of one side, party, or faction only; not mutual

a unilateral decision; unilateral disarmament.

having only one side or surface; without a reverse side or inside, as a Möbius strip.

Law .

pertaining to a contract that can be formed only when the party to whom an offer is made renders the performance for which the offeror bargains.

pertaining to a contract in which obligation rests on only one party, as a binding promise to make a gift.

Botany . having all the parts disposed on one side of an axis, as an inflorescence.

through forebears of one sex only, as through either the mother's or father's line. Compare bilateral ( def. 5 ) .

Phonetics . (of an l -sound) characterized by passage of air on only one side of the tongue.