/ Dictionary / Index S seismism: Meaning and Definition of Find definitions for: seis•mism Pronunciation: (sīz'miz-um, sīs'-), [key] — n. the natural activity or group of phenomena associated with earthquakes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. seismic sea wave seismo- 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