black mustard n
1) a yellow-flowered annual Eurasian herb (Brassica nigra) that is a source of table mustard
2) the dried ripe seed of black mustard or a relative (Brassica juncea) that was formerly much used in medicine as a rubefacient and emetic
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brown mustard Brassica nigra (L.) Koch, a source of volatile oil of mustard and used internally as an emetic and externally as a counterirritant (see mustard plaster, under plaster); it is also used in homeopathy to treat upper respiratory irritation and the gastrointestinal tract. Since the plant contains sinigrin, animals consuming large quantities of it may develop fatal gastroenteritis.Medical dictionary. 2011.