Mustard: a plant of the genus sinapis, a pod-bearing, shrub-like plant, growing wild, and also cultivated in gardens. The little round seeds were an emblem of any small insignificant object. It is not mentioned in the Old Testament; and in each of the three instances of its occurrence in the New Testament (Matt. 13:31, 32; Mark 4:31, 32; Luke 13:18, 19) it is spoken of only with reference to the smallness of its seed. The common mustard of Israel is the Sinapis nigra. This garden herb sometimes grows to a considerable height, so as to be spoken of as "a tree" as compared with garden herbs.