/ Dictionary / Index D deltoidal: Meaning and Definition of Find definitions for: del•toi•dal Pronunciation: (del-toid'l), [key] — adj. of or pertaining to a river delta. deltoid (def. 3). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. deltoid delts 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