Alum — Defs

01 n. A double sulphate formed of aluminium and some other element (esp. an alkali metal) or of aluminium. It has twenty-four molecules of water …

1.
A double sulphate formed of aluminium and some other element (esp. an alkali metal) or of aluminium. It has twenty-four molecules of water of crystallization.(Chem.)

02 v. t. To steep in, or otherwise impregnate with, a solution of alum; to treat with alum.

1.
To steep in, or otherwise impregnate with, a solution of alum; to treat with alum.