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

Sunlight triggers vitamin D production in the skin, and even short periods of daily exposure can make a real impact. — Matthew T. Drake, Fortune, 9 July 2026

Getting the appropriate amount of calcium and vitamin D is essential. — T'keyah Bazin, Verywell Health, 9 July 2026

While spending time outdoors can help boost mood, support the body's production of vitamin D and reduce screen time, dermatologists warn that excessive sun exposure — especially as promoted by the tanmaxxing trend — can be dangerous. — Angelica Stabile, FOXNews.com, 5 July 2026

If vitamin D and ferritin are low, people tend to struggle at altitude. — Adam Crafton, New York Times, 4 July 2026

Word History

First Known Use

circa 1921, in the meaning defined above

Rhymes for vitamin D

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

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