ETYM Latin cohaerentia: cf. French cohérence.
1. Logical and orderly and consistent relation of parts; SYN. coherency.
2. The state of cohering; SYN. coherency, cohesion, cohesiveness.
In physics, property of two or more waves of a beam of light or other electromagnetic radiation having the same frequency and the same phase, or a constant phase difference.

1. In raster-scan technology, the assignment of the value of one pixel to the pixel next to it.
2. In optics, the property of some electromagnetic waves of being in phase with one another, as in light from a laser.