Synonyms for Signature (same or very similar meaning)
WordNet sense 1 (a melody used to identify a performer or a dance band or radio/tv program):
theme song, signature tuneWordNet sense 2 (the sharps or flats that follow the clef and indicate the key):
key signatureWordNet sense 3 (a distinguishing style):
touchFrom the ODE community, based on WordNetadd/edit