What is "white mustard"

Mustard \Mus"tard\, n. [OF. moustarde, F. moutarde, fr. L. mustum must, -- mustard was prepared for use by being mixed with must. See Must, n.]

1. (Bot.) The name of several cruciferous plants of the genus Brassica (formerly Sinapis), as white mustard ( Brassica alba), black mustard ( Brassica Nigra), wild mustard or charlock ( Brassica Sinapistrum).

   Note: There are also many herbs of the same family which are called mustard, and have more or less of the flavor of the true mustard; as, bowyer's mustard ( Lepidium ruderale); hedge mustard ( Sisymbrium officinale); Mithridate mustard ( Thlaspi arvense); tower mustard ( Arabis perfoliata); treacle mustard ( Erysimum cheiranthoides).

2. A powder or a paste made from the seeds of black or white mustard, used as a condiment and a rubefacient. Taken internally it is stimulant and diuretic, and in large doses is emetic.

   Mustard oil (Chem.), a substance obtained from mustard, as a transparent, volatile and intensely pungent oil. The name is also extended to a number of analogous compounds produced either naturally or artificially.

n. Eurasian mustard cultivated for its pungent seeds; a source of table mustard and mustard oil [syn: Brassica hirta, Sinapis alba]

White mustard (Sinapis alba) is an annual plant of the family Brassicaceae. It is sometimes also referred to as Brassica alba or B. hirta. Grown for its seeds, mustard, as fodder crop or as a green manure, it is now widespread worldwide, although it probably originated in the Mediterranean region.