The Collaborative International Dictionary of English v.0.48:

Coagulation \Co*ag`u*la"tion\, n. [L. coagulatio.]
   1. The change from a liquid to a thickened, curdlike,
      insoluble state, not by evaporation, but by some kind of
      chemical reaction; as, the spontaneous coagulation of
      freshly drawn blood; the coagulation of milk by rennet, or
      acid, and the coagulation of egg albumin by heat.
      Coagulation is generally the change of an albuminous body
      into an insoluble modification.
      [1913 Webster]

   2. The substance or body formed by coagulation.
      [1913 Webster]

WordNet (r) 3.0 (2006):

coagulation
    n 1: the process of forming semisolid lumps in a liquid [syn:
         curdling, clotting, coagulation]