n :  a clotting factor that facilitates blood coagulation in vivo and initiates coagulation on a firm surface (as glass) in vitro but whose deficiency tends not to promote hemorrhage - called also Hageman factor  .
 
 
 
Similar sounding terms:  factor XI  factor IX  factor X  factor XIII 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2004.