The name of several cruciferous plants of the genus Brassica (formerly Sinapis), as white mustard (B. alba), black mustard (B. Nigra), wild mustard or charlock (B. Sinapistrum).
- Any of various Eurasian plants of the genus Brassica, especially B. nigra and B. juncea, which are cultivated for their pungent seeds and edible leaves.
- A condiment made from the powdered seeds of certain of these plants.
- A member of the mustard family.
- A dark yellow to light olive brown.