Breadcrumb Home > Dictionary > Index C coseismal: Meaning and Definition of Find definitions for: co•seis•mal Pronunciation: (kō-sīz'mul, -sīs'-), [key] — adj. of, pertaining to, or being in a line, curve, etc., connecting or comprising points on the earth's surface at which an earthquake wave arrives simultaneously. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: coseismal (Thesaurus) cosecant Cosell ✖ Related Content Daily Word Quiz: restive Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language