To burst into bloom, as a plant.To present an appearance of flowering or bursting into bloom; specifically, to become covered with an effiorescence; become incrusted with crystals of salt or the like.In chem., to change either throughout or over the surface to a whitish, mealy, or crystalline powder, from a gradual decomposition, on simple exposure to the air; become covered with a whitish crust or light crystallization, in the form of short threads or spiculæ, from a slow chemical change between some of the ingredients of the matter covered and an acid proceeding commonly from an external source.