having a natural or due agreement of parts; harmonious:
a coherent design.
Physics, Optics. of or relating to waves that maintain a fixed phase relationship, as in coherent light, or light in which the electromagnetic waves maintain a fixed and predictable phase relationship with each other over a period of time.
1550s, from Middle French cohérent (16c.), from Latin cohaerentem (nominative cohaerens), present participle of cohaerere "cohere," from com- "together" (see co-) + haerere "to stick" (see hesitation).