/ Dictionary / Index C coarser: Meaning and Definition of Find definitions for: coars•er Pronunciation: (kôr'sur, kōr'-), [key] — adj. Math. of or pertaining to a topology on a topological space whose open sets are included among the open sets of a second specified topology on the space. Cf. finer. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: coarser (Thesaurus) coarsen coarticulation Related Content Daily Word Quiz: digression Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language