1. (Science: zoology) Any bird of the subfamily Anatinae, family Anatidae.
The genera and species are numerous. They are divided into river ducks and sea ducks. Among the former are the common domestic duck (anas boschas); the wood duck (Aix sponsa); the beautiful mandarin duck of china (Dendronessa galeriliculata); the muscovy duck, originally of south America (Cairina moschata). Among the sea ducks are the eider, canvasback, scoter, etc.
Bombay duck, a small aquatic mammal of australia, having webbed feet and a bill resembling that of a duck (ornithorhynchus anatinus). It belongs the subclass monotremata and is remarkable for laying eggs like a bird or reptile; called also duckbill, platypus, mallangong, mullingong, tambreet, and water mole.
2. A sudden inclination of the bead or dropping of the person, resembling the motion of a duck in water. Here be, without duck or nod, Other trippings to be trod. (Milton)
Origin: oe. Duke, doke.