/ Dictionary / Index V vitamin A aldehyde: Meaning and Definition of Find definitions for: vitamin A aldehyde Pronunciation: [key] retinal. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. vitamin A vitamin B Related Content Daily Word Quiz: clairvoyant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language