<p><strong>Noun</strong></p><ul><li>A pungent powder or paste prepared from the seeds of certain mustard plants, used as a food seasoning or condiment, and medicinally in plasters, poultices, etc.</li><li>Botany: Any of various cruciferous plants of the mustard family, noted for their acrid and pungent qualities and widely cultivated for culinary and agricultural purposes; among the most commercially important mustards are black mustard, brown mustard, and white mustard.</li><li>Nitrogen mustard.</li></ul>