1. Sticking together; cohering.

2. Marked by an orderly, logical, and aesthetically consistent relation of parts: a coherent essay.

3. Physics Of, relating to, or having waves with similar direction, amplitude, and phase that are capable of exhibiting interference.

4. Of or relating to a system of units of measurement in which a small number of basic units are defined from which all others in the system are derived by multiplication or division only.

5. Botany Sticking to but not fused with a part or an organ of the same kind.