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

Prioritizing spending at least some time in natural light every day during winter is one way to boost vitamin D levels; just try to get outside (with sunscreen) for at least 20 minutes each day. —Emma Loewe, Outside, 26 Feb. 2026

Slicing mushrooms before sun exposure may help increase vitamin D production. —Abby Norman, Verywell Health, 26 Feb. 2026

Milk or milk substitutes commonly used in overnight oats also contribute nutrients like calcium and vitamin D, which support bone health, muscle function and nerve signaling. —Daryl Austin, USA Today, 21 Feb. 2026

Manaker notes that milk also provides essential nutrients like calcium, vitamin D, and potassium. —Riley Wofford, Martha Stewart, 21 Feb. 2026

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