Lewis & Short

crasso, no perf., ātum, 1, v. a. [crassus], to make thick, thicken, condense (postclass.): pili crassantur in setas, App. M. 3, p. 139, 39: crassatus aër, Amm. 19, 4, 6; 19, 4, 8; 20, 3, 5.