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

One small study of children with ADHD without magnesium deficiency evaluated the effects of 6 mg per kilogram (kg) of magnesium daily with vitamin D 50,000 international units (IU) a week for eight weeks on ADHD symptoms. —Kirstyn Hill, Pharmd, Mph, Health, 11 Sep. 2024

Soy beverages can be fortified with vitamin A, vitamin D and calcium. —Caroline C. Boyle, USA TODAY, 9 Sep. 2024

In severe cases, long-term vitamin D deficiencies can cause rickets in children and osteoporosis in adults. —Ranyechi Udemezue, Glamour, 4 Sep. 2024

Breast-fed infants often require vitamin D supplementation, like infant formulas which are fortified with vitamin D, as breast milk often does not contain enough of the vitamin. —Kylie Martin, Detroit Free Press, 13 Aug. 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