American watercress n 1: mat-forming perennial found in cold springs of the eastern United States [syn: {American watercress}, {mountain watercress}, {Cardamine rotundifolia}] 2: of southwestern Europe; cultivated in Florida [syn: {Belle Isle cress}, {early winter cress}, {land cress}, {American cress}, {American watercress}, {Barbarea verna}, {Barbarea praecox}]