/ Dictionary / Index C costmary: Meaning and Definition of Find definitions for: cost•mar•y Pronunciation: (kost'mâr"ē, kôst'-), [key] — pl. -mar•ies. a composite plant, Chrysanthemum balsamita, that has silvery, fragrant leaves and is used in salads and as a flavoring. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: costmary (Thesaurus) costly costo- Related Content Daily Word Quiz: blithesome Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language