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).
Origin: OF. Moustarde, F. Moutarde, fr. L. Mustum must, mustard was prepared for use by being mixed with must. See Must.