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alum

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noun al·um \ˈa-ləm\

Definition of alum

  1. 1 :  a potassium aluminum sulfate KAl(SO4)2·12H2O or an ammonium aluminum sulfate NH4Al(SO4)2·12H2O used especially as an emetic and as an astringent and styptic

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

  3. 3 :  aluminum sulfate

Origin and Etymology of alum

Middle English, from Anglo-French alum, alun, from Latin alumen


First Known Use: 14th century

Other Chemical Engineering Terms


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alum

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noun al·um \ə-ˈləm\

Definition of alum

Is it acceptable to use alum for alumnus or alumna?

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.

Origin and Etymology of alum

by shortening


First Known Use: 1910


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alum

abbreviation al·um

Definition of alum

Other Chemical Engineering Terms


ALUM Defined for Kids

alum

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noun al·um \ˈa-ləm\

Definition of alum for Students

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


Medical Dictionary

alum

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noun al·um \ˈal-əm\

Medical Definition of alum

  1. 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 alumb:  one consisting of an ammonium aluminum sulfate NH4Al(SO4)2·12H2O—called also ammonia alum, ammonium alum

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


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