vitamin D

noun

: any or all of several fat-soluble vitamins chemically related to steroids, essential for normal bone and tooth structure, and found especially in fish-liver oils, egg yolk, and milk or produced by activation (as by ultraviolet irradiation) of sterols: such as

a

or vitamin D₂

-ˈdē-ˈtü 

: calciferol

b

or vitamin D₃

-ˈdē-ˈthrē 

: cholecalciferol

Examples of vitamin D in a Sentence

Recent Examples on the Web

The lack of sunlight leads to vitamin D deficiency, which affects bones, muscles and even mood. —Rachel Wolf, FOXNews.com, 14 Oct. 2025

Lifestyle changes like exercising, taking calcium and vitamin D supplements, stopping smoking and drinking only moderately will help, but aren’t sufficient to stop or reverse bone loss, Colon-Emeric said. —The New York Times News Service Syndicate, San Diego Union-Tribune, 14 Oct. 2025

Our chief medical officer, Sohaib Imtiaz, MD, explains the best ways to get your vitamin D without risking unnecessary skin damage from sun exposure. —Claire Bugos, Verywell Health, 8 Oct. 2025

With an adequate amount of vitamin D, good sun protection, a fewer step routine and better eating habits, the glow is continuous. —Samantha Mims, Essence, 3 Oct. 2025

Word History

First Known Use

circa 1921, in the meaning defined above

Rhymes for vitamin D

• abc
• absentee
• addressee
• adoptee
• agouti
• allottee
• amphorae
• amputee
• apc
• apogee
• appointee
• assessee

Kids Definition

vitamin D

noun

: any of several vitamins that are needed for normal bone and tooth structure, and are found especially in fish-liver oils, egg yolk, and milk or are produced in response to ultraviolet light

Medical Definition

vitamin D

noun

: any or all of several fat-soluble vitamins chemically related to steroids, essential for normal bone and tooth structure, and found especially in fish-liver oils, egg yolk, and milk or produced by activation (as by ultraviolet irradiation) of sterols: as

a

: calciferol

b

: cholecalciferol

called also sunshine vitamin