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

Deficient calcification sometimes occurs naturally, but biologists suspect vitamin D deficiency when teeth are regularly stratified by layers of hardened and soft dentin. — Andrew Paul, Popular Science, 5 Nov. 2026

Key Takeaways Omega-3 fatty acids, antioxidants, fiber, magnesium, vitamin D, and plant compounds can help regulate inflammation and support overall health. — Lana Barhum, Verywell Health, 4 Nov. 2026

To help protect cognitive function and prevent brain fog, experts recommend including enough omega-3 fatty acids and antioxidants in your diet while keeping tabs on your vitamin B12, vitamin D, and iron levels. — Tom Gavin, EverydayHealth.com, 2 Nov. 2026

Calcium supplies mineral that helps give bones their strength, while vitamin D helps the body absorb calcium. — Priya Bhardwaj, Washington Post, 31 Oct. 2026

Word History

First Known Use

circa 1921, in the meaning defined above

Rhymes for vitamin D

• abc
• absentee
• addressee
• adoptee
• allottee
• amphorae
• amputee
• apc
• apogee
• appointee
• assessee
• assignee

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