What is "brassica alba"

Sinalbin \Sin*al"bin\, n. [From L. Sinapis + alba.] (Chem.) A glucoside found in the seeds of white mustard ( Brassica alba, formerly Sinapis alba), and extracted as a white crystalline substance.

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.