Merriam-Webster's Collegiate® Dictionary, 11th Edition
CLOT
I. noun see: clout Date: before 12th century a portion of a substance adhering together in a thick nondescript mass (as of clay or gum),
2. a roundish viscous lump formed by coagulation of a portion of liquid or by melting, a coagulated mass produced by clotting of blood, blockhead , cluster , group ,
II. verb (clotted; clotting)
Date: 15th century
intransitive verb to become a clot ; form clots, to undergo a sequence of complex chemical and physical reactions that results in conversion of fluid blood into a coagulated mass ; coagulate , transitive verb to cause to form into or as if into a clot, to fill with clots