[koh-heer-uh
ns, -her-] 
| 1. | the act or state of cohering; cohesion. |
| 2. | logical interconnection; overall sense or understandability. |
| 3. | congruity; consistency. |
| 4. | Physics, Optics. (of waves) the state of being coherent. |
| 5. | Linguistics. the property of unity in a written text or a segment of spoken discourse that stems from the links among its underlying ideas and from the logical organization and development of its thematic content. Compare cohesion (def. 4). |
| co·her·en·cy (kō-hîr'ən-sē) n. pl. co·her·en·cies Coherence. |
| coherence (kō-hîr'əns, -hěr'-) Pronunciation Key
A property holding for two or more waves or fields when each individual wave or field is in phase with every other one. Lasers, for example, emit almost perfectly coherent light; all the photons emitted by a laser have the same frequency and are in phase. Since quantum states can be described by a wave equation, coherence can hold for quantum states in general, though only among bosons. Coherence is generally possible in physical systems that may undergo superposition. Maintaining coherence of light is important in fiber optic communications. See also Bose-Einstein condensate. |