/ Dictionary / Index S simple interval: Meaning and Definition of Find definitions for: sim'ple in'terval Pronunciation: [key] — Music. Music. an interval of an octave or less. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. simple interest simple machine Related Content Daily Word Quiz: nefarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language