/ Dictionary / Index V vitamin D: Meaning and Definition of Find definitions for: vitamin D Pronunciation: [key] any of the several fat-soluble, antirachitic vitamins D, D, D, occurring in milk and fish-liver oils, esp. cod and halibut, or obtained by irradiating provitamin D with ultraviolet light, essential for the formation of normal bones and teeth. vitamin D1 Pronunciation: [key] a mixture of lumisterol and calciferol, obtained by ultraviolet irradiation of ergosterol. vitamin D2 Pronunciation: [key] calciferol. vitamin D3 Pronunciation: [key] a D vitamin, CHOH, occurring in fish-liver oils, that differs from vitamin D by slight structural differences in the molecule. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. vitamin C vitamin E Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language