an electric railway operating below the surface of the ground (usually in a city); "in Paris the subway system is called the `metro' and in London it is called the `tube' or the `underground'"
marked by an orderly, logical, and aesthetically consistent relation of parts; "a coherent argument"
capable of thinking and expressing yourself in a clear and consistent manner; "a lucid thinker"; "she was more coherent than she had been just after the accident"