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.
Advertisement Exceptions are vitamin D, especially for infants, and a few minerals like iron and calcium. Matt Fuchs, Time, 24 Sep. 2025 Researchers have looked at whether vitamin D supplements may lead to weight loss. Sarah Anzlovar, Verywell Health, 24 Sep. 2025 Unlike some nutrients, iron and vitamin D don’t directly influence each other's absorption in the body. Jillian Kubala, Health, 22 Sep. 2025 Sunlight is the body’s main source of vitamin D, which is essential for strong bones and overall health. New Atlas, 21 Sep. 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 30 Sep. 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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