/ Dictionary / Index C costumier: Meaning and Definition of Find definitions for: cos•tum•i•er Pronunciation: (ko-st'mē-ur, -sty'- Fr. kôs-ty-myā'), [key] — pl. cos•tum•i•ers costumer (def. 1). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: costumier (Thesaurus) costumery costuming Related Content Daily Word Quiz: eureka Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language