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

The most common deficiencies are of vitamin B6, iron and vitamin D. Of all the vitamins and minerals, Americans are least likely to be deficient in vitamin A, vitamin E and folate (B9). —Clara Moskowitz, Scientific American, 25 June 2024

Cantaloupe in particular is a good source of vitamin A, a micronutrient that may help reduce chronic inflammation and support eye health. —Karla Walsh, Better Homes & Gardens, 25 June 2024

And there was education that needed to be done: Some of the brand’s products contain ingredients like retinol, a form of vitamin A that can smooth fine lines, and glycolic acid, which helps resurface skin. —Dianna Mazzone Singh, Allure, 20 June 2024

From vitamin A to vitamin C, cantaloupe packs a punch with essential nutrients that can help support your immune and digestive systems, studies have shown. —Caroline C. Boyle, USA TODAY, 11 June 2024

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