The Collaborative International Dictionary of English v.0.48:
Duck \Duck\, n. [OE. duke, doke. See Duck, v. t. ]
1. (Zool.) Any bird of the subfamily Anatin[ae], family
Note: 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.
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.
Bombay duck (Zool.), a fish. See Bummalo.
Buffel duck, Spirit duck. See Buffel duck.
Duck ant (Zool.), a species of white ant in Jamaica which
builds large nests in trees.
Duck barnacle. (Zool.) See Goose barnacle.
Duck hawk. (Zool.)
(a) In the United States: The peregrine falcon.
(b) In England: The marsh harrier or moor buzzard.
Duck mole (Zool.), 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.
To make ducks and drakes, to throw a flat stone obliquely,
so as to make it rebound repeatedly from the surface of
the water, raising a succession of jets; hence:
To play at ducks and drakes, with property, to throw it
away heedlessly or squander it foolishly and unprofitably.
Lame duck. See under Lame.