Treated or caused to react with alum; containing alum.
Mid 18th century; earliest use found in Nathan Bailey (d. 1742), lexicographer and schoolmaster. From classical Latin alūminātus containing alum (from alūmin-, alūmen + -ātus) + -ed; compare -ated.
Combined, alloyed, or caused to react with aluminium; coated with aluminium.
Late 19th century; earliest use found in Items of Interest. From alumin- + -ated.