Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary

Medical Dictionary

factor X

noun \-ˈten\

Medical Definition of factor X

  1. :  a clotting factor that is produced primarily in the liver under the influence of vitamin K and in its activated form is a proteolytic enzyme that converts prothrombin to thrombin in a reaction dependent on calcium ions and phospholipids and accelerated by factor V—called also Stuart-Prower factor

Seen and Heard

What made you want to look up factor X? Please tell us where you read or heard it (including the quote, if possible).