Meaning of mustard gas

mus'tard gas"

Pronunciation: [key]
  1. an oily liquid, CHClS, used as a chemical-warfare gas, blistering the skin and damaging the lungs, often causing blindness and death: introduced by the Germans in World War I. Also called
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.