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 How to pronounce vitamin D (audio)
: calciferol
b
or vitamin D3
-ˈdē-ˈthrē How to pronounce vitamin D (audio)
: cholecalciferol

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.
Patchen studies how omega-3 fatty acids and vitamin D — another nutrient that fish is rich in — are associated with better lung function and lower risk of chronic obstructive pulmonary disease and emphysema. — Diana Anos, CNN Money, 4 Sep. 2026 Calcium and vitamin D are often supplemented together for bone health, but research shows mixed results on their effectiveness in improving bone mineral density or reducing fracture risk. — Jennifer Lefton, Verywell Health, 3 Sep. 2026 Omega-3 supplements with CoQ10 and vitamin D with K can both support collagen synthesis (just check with your primary care doctor before starting them). — Maggie Ryan, Flow Space, 1 Sep. 2026 This looks like prioritizing foods that are high in calcium, vitamin D, and omega-3 fatty acids. — Sarah Madaus, InStyle, 30 Aug. 2026 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

Rhymes for vitamin D

See All Rhymes for vitamin D

Browse Nearby Words

vitamin C
vitamin D
vitamin E
See all Nearby Words

Cite this Entry

“Vitamin D.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/vitamin%20D. Accessed 5 Sep. 2026.

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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

More from Merriam-Webster on vitamin D

Britannica.com: Encyclopedia article about vitamin D

Last Updated: - Updated example sentences
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