1. meaningful interconnections between distinct psychological entities. For example, a system of independent beliefs that is logically consistent from one belief to another would be described as coherent.

2. a measure of the extent to which energy waves (such as light waves) are correlated between two times (temporal coherence) or two points (spatial coherence). Beams of such waves that are in phase, or have a constant phase relationship, are said to be coherent.

3. in imagery, the tendency for an image to be influenced by its background.