To cause (a liquid) to change into a curdlike or semisolid state, not by evaporation but by some kind of chemical reaction; to curdle; as, rennet coagulates milk; heat coagulates the white of an egg
When a liquid coagulates, it becomes very thick. The blood coagulates to stop wounds bleeding. = congeal + coagulation co·agu·la·tion Blood becomes stickier to help coagulation in case of a cut. if a liquid coagulates, or something coagulates it, it becomes thick and almost solid (past participle of coagulare, from cogere; COGENT)