sinapism > define
noun
- A plaster containing powdered black mustard; applied to the skin as a counterirritant or rubefacient.
- synonyms: mustard plaster
by WordNet 3.0 © 2006 by Princeton University
(n.) A plaster or poultice composed principally of powdered mustard seed or containing the volatile oil of mustard seed. It is a powerful irritant.
by Webster's Revised Unabridged Dictionary