vitamin A

noun

: any of several fat-soluble vitamins (such as retinol) that are found especially in green or orange vegetables (such as carrots or spinach) and in animal products (such as egg yolk, butter, or liver) and whose deficiency in the animal body causes epithelial tissues to become keratinous (as in the eye with resulting visual defects)

Examples of vitamin A in a Sentence

Recent Examples on the Web

There is a potential for vitamin A toxicity with an excessive intake of liver. —Sheah Rarback, Miami Herald, 12 Mar. 2026

Retinol is widely regarded as the gold standard of anti-aging ingredients, but for those who really know their vitamin A the best retinal serums can be an even more coveted part of a preventive or anti-aging skin-care routine. —Jenny Berg, Vogue, 11 Mar. 2026

Thanks to its time-rewinding capabilities, the vitamin A derivative is a popular ingredient in plenty of anti-aging products. —Isabel Bekele, InStyle, 11 Mar. 2026

Red bell peppers are higher in calories, sugar, carbohydrates, vitamin A, and vitamin C, while green bell peppers are higher in calcium. —Heidi Moawad, Verywell Health, 7 Mar. 2026

Word History

First Known Use

circa 1920, in the meaning defined above

Kids Definition

vitamin A

noun

: any of several vitamins or a mixture of them that are found especially in green and orange vegetables (as carrots or spinach) and animal products (as egg yolk, butter, or liver) and are needed especially for good vision

Medical Definition

vitamin A

noun

: any of several fat-soluble vitamins or a mixture of two or more of them whose lack in the animal body causes keratinization of epithelial tissues (as in the eye with resulting night blindness and xerophthalmia): as

a

: a pale yellow crystalline highly unsaturated alicyclic alcohol C₂₀H₂₉OH that is found in animal products (as egg yolk, milk, and butter) and especially in marine fish-liver oils (as of cod, halibut, and shark) and that is used in various forms in medicine and nutrition

called also retinol, vitamin A₁

b

: a yellow viscous liquid alicyclic alcohol C₂₀H₂₇OH that contains one more double bond in a molecule than vitamin A₁ and is less active biologically in mammals and that occurs especially in the liver oil of freshwater fish

called also vitamin A₂