noun
Etymology: Middle English waterdokke, from water + dokke, dock, docke dock — more at dock
1. : any of several docks growing in wet places: as
a. : a coarse erect European perennial dock herb ( Rumex hydrolapathum ) with a much-branched inflorescence
b. : a very similar dock ( R. orbiculatus ) of eastern No. America
2. : golden club