1. Of, on, relating to, involving, or affecting only one side: "a unilateral advantage in defense" (New Republic).

2. Performed or undertaken by only one side: unilateral disarmament.

3. Obligating only one of two or more parties, nations, or persons, as a contract or an agreement.

4. Emphasizing or recognizing only one side of a subject.

5. Having only one side.

6. Tracing the lineage of one parent only: a unilateral genealogy.

7. Botany Having leaves, flowers, or other parts on one side only.