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

In response to a rapidly growing measles outbreak in Texas, Kennedy has only tepidly supported vaccination while promoting fringe treatment ideas like vitamin A and cod liver oil, while also downplaying the severity of a measles infection. —Nathaniel Weixel, The Hill, 1 Apr. 2025

Kennedy has said in multiple interviews that vitamin A and cod liver oil are effective measles treatments, per ABC News. —April Rubin, Axios, 31 Mar. 2025

Meanwhile, residents are clearing out local drugstores’ supplies of vitamin A and cod-liver oil, and showing up to a makeshift clinic that is giving out cod-liver oil. —Nicholas Florko, The Atlantic, 28 Mar. 2025

The presence of vitamin A in milk further aids in immune function and vision health, while B vitamins contribute to energy production and red blood cell formation, said the nutrition expert. —Erica Lamberg, Fox News, 23 Mar. 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