I. ˈa-ləm noun
Etymology: Middle English, from Anglo-French alum, alun, from Latin alumen
Date: 14th century
1. : a potassium aluminum sulfate KAl(SO 4 ) 2 ·12H 2 O or an ammonium aluminum sulfate NH 4 Al(SO 4 ) 2 ·12H 2 O used especially as an emetic and as an astringent and styptic
2. : any of various double salts isomorphous with potassium aluminum sulfate
3. : aluminum sulfate
II. ə-ˈləm noun
Etymology: by shortening
Date: 1930
: alumnus , alumna
III. abbreviation
aluminum