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.-the substance or body formed by coagulation.