1.Definition: (physics) of waves having a constant phase relation
2.Definition: capable of thinking and expressing yourself in a clear and consistent manner
"She was more coherent than she had been just after the accident"
3.Definition: marked by an orderly, logical, and aesthetically consistent relation of parts
"A coherent argument"
Related Adjective(s):consistent, logical, ordered
4.Definition: sticking together
"Two coherent sheets"