- any one of a group of substances, including factor VIII, the presence of which in the blood is essential for blood clotting to occurAlso called: coagulation factor
- Any of various plasma components involved in the clotting of blood, including fibrinogen, prothrombin, thromboplastin, and calcium ion.coagulation factor
- Any of various components of plasma involved in the coagulation of blood, including fibrinogen, prothrombin, and calcium ions. Hereditary deficiency of clotting factors can cause coagulation disorders such as hemophilia.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.