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

Some studies have found that taking vitamin D may improve magnesium levels in people with low magnesium and vitamin D levels. —Kirstyn Hill, Pharmd, Mph, Health, 13 Jan. 2025

Combining zinc and vitamin D has been shown to be more effective in decreasing depressive symptoms than vitamin D alone, according to Nutrition. —Amiah Taylor, Discover Magazine, 25 Dec. 2024

People with darker skin tend to be more deficient in vitamin D — but SPF is still beneficial. —Jacqueline Kilikita, refinery29.com, 5 Dec. 2024

Foods containing vitamin D include egg yolks, liver, and saltwater fish, as well as foods fortified with vitamin D, such as milk, cereal, and yogurt.13 Two kinds of vitamin D supplements are available: Vitamin D2 and D3. —Ashley Wong, Health, 2 Jan. 2025

Word History

First Known Use

circa 1921, in the meaning defined above

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