from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Light of a uniform wavelength and phase; as used in lasers
from the GNU version of the Collaborative International Dictionary of English
- n. Light in which the phases of all electromagnetic waves at each point on a line normal to the direction of the the beam are identical. Coherent light is usually monochromatic, and the most common source of such light for practical uses is from a laser.
Sorry, no etymologies found.