alum

noun (1)

al·um | \ ˈa-ləm

Definition of alum

(Entry 1 of 3)

1 : a potassium aluminum sulfate KAl(SO₄)₂·12H₂O or an ammonium aluminum sulfate NH₄Al(SO₄)₂·12H₂O used especially for its astringent and styptic properties

2 : any of various double salts isomorphous with potassium aluminum sulfate

3 : aluminum sulfate

alum

noun (2)

\ ə-ˈləm

Definition of alum (Entry 2 of 3)

: alumnus, alumna a Yale alum

alum

abbreviation

Definition of alum (Entry 3 of 3)

aluminum

Is it acceptable to use alum for alumnus or alumna?

Noun (2)

The words that we have used to refer to people who have attended or graduated from a school, college, or university have changed a bit over the past several centuries. Traditionally, the word alumnus has been used to refer to a single male, whereas alumna has been used for a single woman. Initially the plural forms were alumni to refer to multiple men (or multiple men and women) and alumnae for multiple women. A little over a hundred years ago the shortened form of alum began to be used to describe a graduate or past attendee of either gender. Although many people feel that alum is informal, it is in increasing use, and we appear to be moving toward a greater acceptance of the word. The plural of alum is alums.

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The first known use of alum was in the 14th century

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More Definitions for alum

alum

noun

al·um | \ ˈa-ləm

Kids Definition of alum

: either of two aluminum compounds that are used especially in medicine (as to stop bleeding)

alum

noun

al·um | \ ˈal-əm

Medical Definition of alum

1 : either of two colorless or white crystalline double sulfates of aluminum used in medicine internally as emetics and locally as astringents and styptics:

a : one KAl(SO₄)₂·12H₂O that is a sulfate of aluminum and potassium

— called also potassium alum