WordWeb Online

1. Marked by an orderly, logical, and aesthetically consistent relation of parts
   "a coherent argument";
   - consistent, logical, ordered
    
2. (physics) of waves having a constant phase relation
    
3. Capable of thinking and expressing yourself in a clear and consistent manner
   "she was more coherent than she had been just after the accident";
   - logical, lucid
    
4. Sticking together
   "two coherent sheets";
   - tenacious

See also: adhesive, logical, rational, seamless

Antonym: incoherent

Encyclopedia: Coherent