/ Dictionary / Index C Costa Mesa: Meaning and Definition of Find definitions for: Cos•ta Me•sa Pronunciation: (kos'tu mā'su, kô'stu, kō'-), [key] a city in SW California, near Los Angeles. 82,291. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. costal Costanoan Related Content Daily Word Quiz: penchant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language