coherent

Concise Oxford English Dictionary © 2008 Oxford University Press:
coherent/kəʊˈhɪərənt/

▶adjective

• 1 (of an argument or theory) logical and consistent.

  ■ able to speak clearly and logically.

• 2 holding together to form a whole.

• 3 Physics (of waves) having a constant phase relationship.

– derivatives
coherence noun,
coherency noun,
coherently adverb.