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 : calciferol
b

Examples of vitamin D in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The lack of sunlight leads to vitamin D deficiency, which affects bones, muscles and even mood. Rachel Wolf, FOXNews.com, 14 Oct. 2025 Lifestyle changes like exercising, taking calcium and vitamin D supplements, stopping smoking and drinking only moderately will help, but aren’t sufficient to stop or reverse bone loss, Colon-Emeric said. The New York Times News Service Syndicate, San Diego Union-Tribune, 14 Oct. 2025 Our chief medical officer, Sohaib Imtiaz, MD, explains the best ways to get your vitamin D without risking unnecessary skin damage from sun exposure. Claire Bugos, Verywell Health, 8 Oct. 2025 With an adequate amount of vitamin D, good sun protection, a fewer step routine and better eating habits, the glow is continuous. Samantha Mims, Essence, 3 Oct. 2025 See All Example Sentences for vitamin D

Word History

First Known Use

circa 1921, in the meaning defined above

Time Traveler
The first known use of vitamin D was circa 1921

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Cite this Entry

“Vitamin D.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/vitamin%20D. Accessed 22 Oct. 2025.

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
b
: cholecalciferol

called also sunshine vitamin

More from Merriam-Webster on vitamin D

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