- a cruciferous plant (Sinapis alba) grown for its culinary seeds and valued as an efficient crop for fodder and green manure: the seeds, which are significantly milder than black mustard seeds, are commonly used whole in pickling and finely crushed in the preparation of yellow mustard.
- a Eurasian plant, Brassica hirta (or Sinapis alba), having clusters of yellow flowers and pungent seeds from which the condiment mustard is made: family Brassicaceae (crucifers)
