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menadione

[men-uh-dahy-ohn]
noun Pharmacology.
  1. a synthetic yellow crystalline powder, C11H8O2, insoluble in water, used as a vitamin K supplement.
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Origin of menadione

First recorded in 1940–45; me(thyl) + na(phthalene) + di-1 + -one
Also called vitamin K3.

vitamin K1

noun
  1. a yellowish, oily, viscous liquid, C31H46O2, occurring in leafy vegetables, rice, bran, hog liver, etc., or obtained especially from alfalfa or putrefied sardine meat, or synthesized, that promotes blood clotting by increasing the prothrombin content of the blood.
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Origin of vitamin K1

First recorded in 1930–35
Also called phylloquinone, phytonadione.

vitamin K2

noun
  1. a light-yellow, crystalline solid, C41H56O2, having properties similar to those of vitamin K1.
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vitamin K3

noun
  1. menadione.
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Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for vitamin k

vitamin K

noun plural K vitamins
  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 K1

noun
  1. another name for phylloquinone
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vitamin K2

noun
  1. another name for menaquinone
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vitamin K3

noun
  1. a former name for menadione
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menadione

noun
  1. a yellow crystalline compound used in fungicides and as an additive to animal feeds. Formula: C 11 H 8 O 2Also: vitamin K 3
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Word Origin

C20: from me (thyl) + na (phtha) + di- 1 + -one
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
vitamin k in Medicine

vitamin K

n.
  1. Any of several fat-soluble compounds that are found in alfalfa, hog liver, fish meal, and vegetable oils and are essential for the production of normal amounts of prothrombin.antihemorrhagic factor
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menadione

(mĕn′ə-dī′ōn′)
n.
  1. A synthetic vitamin K derivative occurring as a yellow crystalline powder and used as a vitamin K supplement.
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vitamin K1

n.
  1. A yellow viscous oil found in leafy green vegetables or made synthetically, used by the body to form prothrombin.
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vitamin K2

n.
  1. Any of various yellowish crystalline compounds isolated from putrefied fish meal or from various intestinal bacteria and used to stop hemorrhaging.menaquinone
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The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
vitamin k in Science

vitamin K

  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 K1, which is synthesized by plants, and vitamin K2, which is mainly synthesized by intestinal bacteria. The other forms are synthetic substances with similar chemical structures.
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vitamin K1

  1. The major dietary form of vitamin K that is synthesized in plants and found primarily in green, leafy vegetables such as alfalfa and in vegetable oils. It can be made synthetically and is given orally to treat prothrombin deficiency that results from heparin and other anticoagulant drugs. Also called phylloquinone. Chemical formula: C31H46O2.
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vitamin K2

  1. A form of vitamin K that is synthesized by bacteria in the intestine and is also found in fish and other foods. Also called menaquinone. Chemical formula: C41H56O2.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.