Quantcast
Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary
1

alum

play
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


2

alum

play
noun al·um \ə-ˈləm\

Definition of alum



Origin and Etymology of alum

by shortening


First Known Use: 1910


3

alum

abbreviation al·um

Definition of alum



Other Chemical Engineering Terms


ALUM Defined for Kids

alum

play
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

play
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




Learn More about alum


Seen and Heard

What made you want to look up alum? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

of, relating to, or near a shore

Get Word of the Day daily email!

WORD GAMES

Take a 3-minute break and test your skills!

lavender-fields-in-france

Which of these is a synonym of caesura?

torrent rebellion megillah interruption
Name That Thing

Test your visual vocabulary with our 10-question challenge!

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ