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

Adequate vitamin D levels can help your body fight infections and may lower the risk of autoimmune disease. —Abby Norman, Verywell Health, 21 Jan. 2026

By feeding on smaller organisms that produce vitamin D from sunlight, the nutrient becomes stored in the fish’s fat. —Jillian Kubala, Health, 21 Jan. 2026

The pantry staple also provides protein and vitamin D, which are key for healthy muscles and bones, respectively. —Olivia McIntosh, Martha Stewart, 18 Jan. 2026

The mass fruiting event last took place in 2022, and according to reports from the Washington Post and the Guardian, conservationists were relieved this year to observe a bumper crop of the tree's berrylike fruit, which serve as a source of calcium and vitamin D for the birds. —Charlotte Phillipp, PEOPLE, 16 Jan. 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