arugula (n.) Look up arugula at Dictionary.com
edible cruciform plant (Eruca sativa) used originally in the Mediterranean region as a salad; the American English and Australian form of the name is (via Italian immigrants) from dialectal variant of Italian ruchetta, a diminutive form of ruca-, from Latin eruca, a name of some cabbage-like plant, from PIE *gher(s)-uka-, from root *ghers- "to bristle" (see horror).

In England, the usual name is rocket (see rocket (n.1)), which is from Italian ruchetta via French roquette. It also sometimes is called hedge mustard.