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

Liver Liver, an organ meat, is a rich source of protein, B vitamins, vitamin A, iron, and many other nutrients needed for optimal immune function. —Jillian Kubala, Health, 16 Dec. 2024

Studies from the American Journal of Clinical Nutrition show that a diet high in vitamin A can help improve vision in dim light and reduce the risk of night blindness. —Maria Berentzen, Vogue, 12 Dec. 2024

Eggs are chock-full of protein, iron, vitamin A, vitamin B12 and fatty acids, according to the American Kennel Club. —Olivia Munson, USA TODAY, 9 Dec. 2024

The foundation says that reptiles should gain adequate weight during the summer months, particularly through diets rich in vitamin A, to sustain themselves during their dormant phase. —Jason Fields, Newsweek, 5 Dec. 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