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

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

As an example, low levels of vitamin D in children can lead to a condition called rickets, which results in weak bones, poor growth and bone deformities. —Omer Awan, Forbes, 1 Jan. 2025

Daylight also brings fresh air and the production of vitamin D into play. —Desireé Oostland, Vogue, 31 Dec. 2024

Zinc also has a synergistic relationship with vitamin D, acting as a cofactor for vitamin D functions and aids vitamin D to work inside human cells. —Amiah Taylor, Discover Magazine, 25 Dec. 2024

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