Definition of Alum in English :

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Alum meaning in English

Meaning of Alum in English

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Alum

see synonyms of alum

Noun

1. alum, ammonia alum, ammonium alum

a white crystalline double sulfate of aluminum: the ammonium double sulfate of aluminum

2. alum, potash alum, potassium alum

a white crystalline double sulfate of aluminum: the potassium double sulfate of aluminum

3. alum, alumna, alumnus, grad, graduate

a person who has received a degree from a school (high school or college or university)

4. alum

a double sulphate of aluminum and potassium that is used as an astringent (among other things)

WordNet Lexical Database for English. Princeton University. 2010.


Alum

see synonyms of alum
noun
1. Also called: potash alum
a colourless soluble hydrated double sulphate of aluminium and potassium used in the manufacture of mordants and pigments, in dressing leather and sizing paper, and in medicine as a styptic and astringent. Formula: K2SO4.Al2(SO4)3.24H2O
2. 
any of a group of isomorphic double sulphates of a monovalent metal or group and a trivalent metal. Formula: X2SO4.Y2(SO4)3.24H2O, where X is monovalent and Y is trivalent
noun
informal, mainly US and Canadian
an alumnus or alumna

Collins English Dictionary. Copyright © HarperCollins Publishers


Alum

see synonyms of alum
noun
1. 
a double sulfate of a monovalent metal or radical (as sodium, potassium, or ammonium) with a trivalent metal (as aluminum, iron, or chromium): it is used as an astringent, as an emetic, and in the manufacture of baking powders, dyes, and paper: the commonest form is potash alum (potassium aluminum sulfate), KAl(SO4)2·12H2O
2. 
aluminum sulfate: an erroneous use
noun
Informal
an alumnus or alumna

Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by Houghton Mifflin Harcourt. All rights reserved.


Alum

see synonyms of alum
n.
Any of various double sulfates of a trivalent metal such as aluminum, chromium, or iron and a univalent metal such as potassium or sodium, especially hydrous aluminum potassium sulfate, AlK(SO4)2·12H2O, widely used in industry as clarifiers, hardeners, and purifiers and medicinally as topical astringents and styptics.
n.
Informal
An alumna or alumnus.

The American Heritage ® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.