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

To maintain healthy bones, establish a regular exercise routine that includes weight training, and incorporate foods rich in vitamin D and calcium into your diet. —Caroline C. Boyle, USA Today, 21 Apr. 2025

So, people who rely on specific nutrients like vitamin D for bone health or folic acid during pregnancy might want to use vitamins before their expiration date. —Emmanuella Ogbonna, Health, 21 Apr. 2025

The primary source of vitamin D is exposure to the sun’s ultraviolet (UV) rays. —Melissa Rudy, FOXNews.com, 19 Apr. 2025

Bonus: get outside — sunlight triggers natural vitamin D production. —Allison Palmer, Miami Herald, 14 Apr. 2025

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