the GNU version of the Collaborative International Dictionary of English
n. A plaster or poultice composed principally of powdered mustard seed, or containing the volatile oil of mustard seed. It is a powerful irritant.
The Century Dictionary and Cyclopedia
n. A plaster composed wholly or in part of mustard-flour; a mustard-plaster.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. a plaster containing powdered black mustard; applied to the skin as a counterirritant or rubefacient
Word Usage
"It is the black Mustard which yields by its seeds the condiment of our tables, and the pungent yellow flour which we employ for the familiar stimulating poultice, or sinapism."