1.NounAny of a specific group of organic compounds essential in small quantities for healthy human growth, metabolism, development, and body function. They are found in minute amounts in plant and animal foods or sometimes produced synthetically, and deficiencies of specific vitamins produce specific disorders.
"a food rich in vitamins"
2.Nounpreceding a word or its initial letter, to imply that the referent benefits health or wellness
"Vitamin N: The Essential Guide to a Nature-Rich Life; I just follow three three Cs: clean living, chewing thoroughly, and a daily dose of vitamin Church"