Definition of "oleum" []

• A corrosive solution of sulfur trioxide in sulfuric acid. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The Associated Press reports that last Saturday, October 12th, at 5 pm the plant experienced a leakage of a substance called oleum that overflowed a tank and instantly evaporated."
• "A material called oleum, similar to sulfuric acid, leaked from a tank at the Indspec Chemical Corp. plant in Petrolia, said plant manager Dave Dorko."
• "Material called oleum, like sulfuric acid, leaked at the Indspec Chemical Corp."