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

Look to the key vitamins found in the bouncy formula, including vitamin A (retinol), vitamin B (niacinamide), and vitamin C (yuzu extract). —Sarah Han, Allure, 25 Apr. 2025

Texas Public Media reported that several children in West Texas were hospitalized with vitamin A toxicity following his Fox News statement. —Geoff Brumfiel, NPR, 7 Apr. 2025

The latest: West Texas children treated for vitamin A toxicity after measles hospitalizations What are measles' symptoms? Measles symptoms can begin a week or two after infection and can include high fever, cough, runny nose and watery, red eyes. —Phaedra Trethan, USA Today, 6 Apr. 2025

Ensuring your diet is rich in fruits, vegetables, and proteins will help support nail growth (these foods contain nutrients needed for nail growth, like amino acids, vitamin C, magnesium, vitamin D, vitamin A, and vitamin B6, among others, explains Dr. Patel). —Catharine Malzahn, Glamour, 3 Apr. 2025

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