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

Tofu is rich in other vitamins and minerals such as vitamin A, iron, and manganese. — Suchandrima Bhowmik, HEALTH, 6 Nov. 2026

Carrots and sweet potatoes are both starchy and sweet root vegetables rich in vitamin A and beta-carotene (which the body converts into vitamin A), but each offers a unique nutritional profile and potential health benefits. — Anna Giorgi, Verywell Health, 2 Nov. 2026

The proposal decreases the amount of vitamin A required in formula, from 250 international units per 100 calories to 233 IU. — Brenda Goodman, CNN Money, 29 Oct. 2026

Overuse of vitamin A can lead to side effects ranging from skin irritation and hair loss to fatigue and bone and joint pain. — Maggie Ryan, Flow Space, 26 Oct. 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