- the cruciferous plant Brassica nigra, the seeds of which are ground into a pungent spice or used whole, as in Indian cuisine, and are a chief ingredient of many commercially prepared mustards: black mustard is sometimes mistakenly classified as Sinapis nigra, but it does not belong to same genus as white mustard (S. alba).
- a Eurasian plant, Brassica (or Sinapsis) nigra, with clusters of yellow flowers and pungent seeds from which the condiment mustard is made: family Brassicaceae (crucifers)
