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

In addition to its vitamin D benefits, rainbow trout is also an excellent source of high-quality protein, omega-3 fatty acids, and essential minerals like selenium and potassium. —Kelly Burch, Verywell Health, 28 Nov. 2025

It's typically measured in international units (IU) or micrograms (mcg), and dosages aren't broken down by vitamin D type. —Lindsey Desoto, Health, 24 Nov. 2025

Most Americans need to increase their intake of dietary fiber, calcium, vitamin D, and potassium, the agency notes. —Youri Benadjaoud, ABC News, 19 Nov. 2025

Dark skin in cloudy places blocked the production of vitamin D in the skin, which is necessary for normal bone growth in children and adults. —Michael A. Little, The Conversation, 17 Nov. 2025

Word History

First Known Use

circa 1921, in the meaning defined above

Rhymes for vitamin D

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

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