Wordnet 3.0
NOUN (1)
1.
oil obtained from mustard seeds and used in making soap;
The Collaborative International Dictionary of English v.0.48:
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).
[1913 Webster]
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).
[1913 Webster]
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.
[1913 Webster]
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.
[1913 Webster]
WordNet (r) 3.0 (2006):
mustard oil
n 1: oil obtained from mustard seeds and used in making soap