radish, herbaceous plant ( Raphanus sativus ) belonging to the family Cruciferae (mustard family), with an edible, pungent root sliced in salads or used as a relish. It is thought to be native to China; it spread to the Mediterranean area before Greek times and to the New World in the early 16th cent. There are many varieties, with white, red, or black roots of different shapes and sizes, some quite large. Radishes grow easily and quickly throughout temperate regions; they are a staple food in Japan and China, where they are generally pickled in brine. Radishes are classified in the division Magnoliophyta, class Magnoliopsida, order Capparales, family Cruciferae.