Meaning of alum

al•um

Pronunciation: (al'um), [key]
— n. Chem.
  1. Also calleda crystalline solid, aluminum potassium sulfate, KSO&multiplydot;Al(SO)&multiplydot;24HO, 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 RSO&multiplydot;X(SO)&multiplydot;24HO, 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.

a•lum

Pronunciation: (u-lum'), [key]
— n. Informal.
  1. an alumna or alumnus.

alum.

Pronunciation: [key]
— Chem. Chem.
  1. aluminum.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
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