A genus of plants embracing several species and varieties differing much in appearance and qualities: such as the common cabbage (Brassica oleracea), broccoli, cauliflowers, etc.; the wild turnip (Brassica campestris); the common turnip (Brassica rapa); the rape or coleseed (Brassica napus), etc. [1913 Webster]
Brassica, n. any cruciferous plant of the genus Brassica, having tap roots and erect branched stems, including cabbage, swede, brussel sprout, mustard, rape, cauliflower, kohlrabi, calabrese, kale, and turnip.