/ Dictionary / Index S signature tune: Meaning and Definition of Find definitions for: sig'nature tune". Pronunciation: [key] See(def. 2). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. signature loan signboard Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language