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alum - 12 dictionary results
al⋅um
1
[al-uh
m] 
–noun Chemistry.
| 1. | Also called potash alum, potassium alum. a crystalline solid, aluminum potassium sulfate, K2SO4·Al2(SO4)3·24H2O, used in medicine as an astringent and styptic, in dyeing and tanning, and in many technical processes. |
| 2. | one of a class of double sulfates analogous to the potassium alum, as aluminum ammonium sulfate, having the general formula R2SO4·X2(SO4)3·24H2O, where R is a univalent alkali metal or ammonium, and X one of a number of trivalent metals. |
| 3. | (not in technical use) aluminum sulfate. |
Origin:
1275–1325; ME < AF < L alūmen; r. OE alefne, ælifnæ < OWelsh (cf. MWelsh elyf) < L alūmini- (s. of alūmen)
1275–1325; ME < AF < L alūmen; r. OE alefne, ælifnæ < OWelsh (cf. MWelsh elyf) < L alūmini- (s. of alūmen)
a⋅lum
2 [uh-luhm] –noun Informal.
| an alumna or alumnus. |
Origin:
by shortening
by shortening
alum.
Chemistry.
| aluminum. |
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
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Based on the Random House Dictionary, © Random House, Inc. 2009.
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Link To alum
| al·um 1 (āl'əm) 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. [Middle English, from Old French, from Latin alūmen.] |
| a·lum 2 (ə-lŭm') n. Informal An alumna or alumnus. |
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Alum
Al"um\, n. [OE. alum, alom, OF. alum, F. alun, fr. L. alumen alum.] (Chem.) A double sulphate formed of aluminium and some other element (esp. an alkali metal) or of aluminium. It has twenty-four molecules of water of crystallization. Note: Common alum is the double sulphate of aluminium and potassium. It is white, transparent, very astringent, and crystallizes easily in octahedrons. The term is extended so as to include other double sulphates similar to alum in formula.Alum
Al"um\, v. t. To steep in, or otherwise impregnate with, a solution of alum; to treat with alum. --Ure.
Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.
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alum
c.1325, "whitish mineral salt used as an astringent, dye, etc.," from O.Fr. alum, from L. alumen "alum," lit. "bitter salt," cognate with Gk. aludoimos "bitter" and Eng. ale.
Online Etymology Dictionary, © 2001 Douglas Harper
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Main Entry: al·um
Pronunciation: 'al-&m
Function: noun
1 : either of two colorless or white crystalline double sulfates of aluminum usedin medicine internally as emetics and locally as astringents and styptics: a : one KAl(SO4)2·12H2O that is a sulfate of aluminum and potassiumcalled also potassium alum b : one consisting of an ammonium aluminum sulfate NH4Al(SO4)2·12H2O called also ammoniaalum, ammonium alum
2 : any of various double salts isomorphous with potassium aluminum sulfate
Merriam-Webster's Medical Dictionary, © 2002 Merriam-Webster, Inc.
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alum al·um (āl'əm)
n.
Any of various double sulfates of a trivalent metal such as aluminum or iron and a univalent metal such as potassium or sodium that are used as topical astringents and styptics.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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| alum (āl'əm) Pronunciation Key
Any of various crystalline double salts of a trivalent metal (such as aluminum, chromium, or iron) and a monovalent metal (such as potassium or sodium), especially aluminum potassium sulfate. Alum is widely used in industry as a hardener and purifier, and in medicine as an emetic and to stop bleeding. |
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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alum
|
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Copyright © 2009, Dictionary.com, LLC. All rights reserved.
