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

This finding held true even after researchers accounted for age, time since menopause, vitamin D levels, smoking status, and other health conditions. —Rob Williams, EverydayHealth.com, 15 June 2026

Taking a vitamin D supplement with black coffee or on an empty stomach meaningfully reduces how much your body can actually use. —Allison Palmer updated June 13, Sacbee.com, 13 June 2026

The goal is not avoiding the sun, which still supports vitamin D synthesis, mood and circadian rhythm. —Allison Palmer updated June 13, Fort Worth Star-Telegram, 13 June 2026

Time outdoors supports vitamin D synthesis, mood and circadian rhythm. —Allison Palmer updated June 13, Miami Herald, 13 June 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