the GNU version of the Collaborative International Dictionary of English
adj. Containing alum.
The Century Dictionary and Cyclopedia
Containing or yielding alum, alumina, or aluminium.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. containing alum or aluminum
Word Usage
"The Oxford English Dictionary even contains an entry for rock butter, "a mineral composed of alum combined with iron, which exudes as a soft butter-like paste from certain aluminiferous rocks.""