vitamin K

noun

1

: either of two naturally occurring fat-soluble vitamins essential for the clotting of blood because of their role in the production of clotting factors in the liver:

a

or vitamin K₁

-ˈkā-ˈwən 

: the vitamin C₃₁H₄₆O₂ that is produced by plants and obtained especially from green leafy vegetables (such as collards and kale)

b

or vitamin K₂

-ˈkā-ˈtü 

: the vitamin C₄₁H₅₆O₂ that is produced by bacteria (as in the intestines of animals) and obtained especially from meat and fermented foods

2

a

or vitamin K₃

-ˈkā-ˈthrē 

: menadione

b

: any of several synthetic compounds chemically related to menadione

Examples of vitamin K in a Sentence

Recent Examples on the Web

The high vitamin K levels in these types of veggies can make the drugs less efficient at preventing blood clots. —Katie Camero, SELF, 13 Sep. 2024

The formula does contain blackberry extract, an ingredient packed with brightening vitamin C, healing vitamin K and vitamin A (essentially what retinol is derived from). —Venus Wong, refinery29.com, 5 Sep. 2024

Certain medications may decrease vitamin K absorption in the body. —Jamie Johnson, Verywell Health, 15 Aug. 2024

Severe symptoms of vitamin K deficiency can include bleeding and hemorrhaging, Thomason notes. —Hannah Yasharoff, USA TODAY, 13 Aug. 2024

Word History

Etymology

from the initial letter of Danish & Swedish koagulation coagulation, Norwegian koagulasjon & German Koagulation

First Known Use

1935, in the meaning defined at sense 1

Kids Definition

vitamin K

noun

: any of several vitamins that are needed in order for blood to clot properly

Medical Definition

vitamin K

noun

1

: either of two naturally occurring fat-soluble naphthoquinone vitamins essential for the clotting of blood because of their role in the production of clotting factors in the liver:

a

or vitamin K₁

-ˈkā-ˈwən 

: a yellow oily vitamin C₃₁H₄₆O₂ that is produced by plants and obtained especially from green leafy vegetables (such as collards and kale) and is often used to treat hypoprothrombinemia

called also phylloquinone, phytonadione

b

or vitamin K₂

-ˈkā-ˈtü 

: a pale yellow crystalline vitamin C₄₁H₅₆O₂ that is produced by bacteria (as in the intestines of animals) and obtained especially from meat and fermented foods and that typically has greater bioavailability than vitamin K₁

called also menaquinone

2

a

or vitamin K₃

-ˈkā-ˈthrē 

: menadione

b

: any of several synthetic compounds chemically related to menadione