vitamin D

American  

noun

1. any of the several fat-soluble, antirachitic vitamins D 1 , D 2 , D 3 , occurring in milk and fish-liver oils, especially cod and halibut, or obtained by irradiating provitamin D with ultraviolet light, essential for the formation of normal bones and teeth.

---

vitamin D British  

noun

1. any of the fat-soluble vitamins, including calciferol and cholecalciferol, occurring in fish-liver oils (esp cod-liver oil), milk, butter, and eggs: used in the treatment of rickets and osteomalacia

---

vitamin D Scientific  

1. Any of a group of fat-soluble sterols necessary for normal bone growth, especially vitamin D ₂ (ergocalciferol) and vitamin D ₃ (cholecalciferol). Vitamin D is found in milk, fish, and eggs and can be produced in the skin on exposure to sunlight. A deficiency of vitamin D in the diet causes rickets in children.

---

Etymology

Origin of vitamin D

First recorded in 1920–25

Example Sentences

Researchers measured each participant's blood vitamin D level at the start of the study.

From Science Daily • Apr. 7, 2026

Whilst exposure to small amounts of UV radiation is essential to produce vitamin D, the World Health Organization warns "overexposure may result in acute and chronic health effects on the skin, eye and immune system".

From BBC • Mar. 18, 2026

Advice from the NHS, external is to "strike a balance between protecting yourself from the Sun and getting enough vitamin D from sunlight".

From BBC • Mar. 18, 2026

Over the four week study period, the researchers found no meaningful difference between the vitamin D and placebo groups in terms of healthcare utilization or death.

From Science Daily • Mar. 15, 2026

“A, B, C, vitamin D, vitamin D, vitamin D . . .” The Super-Vox-Wurlitzeriana had risen to a sobbing crescendo; and suddenly the verbena gave place, in the scent- circulating system, to an intense patchouli.

From "Brave New World" by Aldous Huxley