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

Messer notes that bell peppers are also excellent sources of vitamin A – primarily in the form of beta-carotene – which supports healthy vision, immune function and normal cell growth. — Daryl Austin, USA Today, 29 July 2026

Retinol is a form of vitamin A that helps skin behave in a healthier, more youthful-looking way, Kilgore explains to me. — Rachel Burchfield, Forbes.com, 29 July 2026

Spinach beats out kale for vitamin A, folate, iron, and magnesium. — Jillian Kubala, Health, 25 July 2026

Your body converts beta-carotene into vitamin A, which is essential for normal skin cell growth and maintenance. — Kathleen Ferraro, Verywell Health, 24 July 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