vitamin K

British  

noun

1. any of the fat-soluble vitamins, including phylloquinone and the menaquinones, which are essential for the normal clotting of blood

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vitamin K Scientific  

1. Any of a group of fat-soluble vitamins that are involved in the formation of prothrombin and other clotting factors in the liver and are essential for normal clotting of the blood. (The K is derived from the German word koagulation.) Vitamin K is also involved in bone formation and repair. Two forms occur naturally: vitamin K ₁, which is synthesized by plants, and vitamin K ₂, which is mainly synthesized by intestinal bacteria. The other forms are synthetic substances with similar chemical structures.

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Example Sentences

To better understand how vitamin K protects neurons, the team compared gene expression patterns in neural stem cells treated with MK-4, which promotes neuronal differentiation, to those treated with a compound that suppresses it.

From Science Daily • Oct. 14, 2025

Coroner Lorna Skinner KC said he would not have died had he been given vitamin K, needed for blood clotting.

From BBC • Oct. 27, 2023

One hypothesis is that the vitamin K plus potassium and magnesium may help with bone remineralization.

From Seattle Times • Sep. 27, 2023

Biologists trapped him, treated him with topical medications and vitamin K injections and released him.

From Los Angeles Times • Dec. 13, 2022

After suctioning the mucus from my nostrils, she gave me a shot of vitamin K to coagulate my blood.

From "Middlesex: A Novel" by Jeffrey Eugenides