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

In addition to vitamin D, kefir is packed with immune-boosting probiotics. —Kelly Burch, Verywell Health, 5 Mar. 2026

Other than fiber, Americans are also deficient in vitamin D, calcium, and potassium, according to the 2020-2025 Dietary Guidelines for Americans. —Jake Angelo, Fortune, 1 Mar. 2026

In these cases, your best bet is to get vitamin D from foods such as fatty fish, egg yolks, and cheese, or a supplement. —Emma Loewe, Outside, 26 Feb. 2026

Athletes need vitamins, too After satisfying their macronutrient needs, athletes need micronutrients, especially vitamin D and iron. —Claire Cameron, Scientific American, 11 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