/ Dictionary / Index S simple harmonic motion: Meaning and Definition of Find definitions for: sim'ple harmon'ic mo'tion Pronunciation: [key] — Physics. Physics. vibratory motion in a system in which the restoring force is proportional to the displacement from equilibrium. Abbr.: S.H.M., s.h.m. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. simple group simple-hearted Related Content Daily Word Quiz: fidelity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language