The Collaborative International Dictionary
duck egg
Goose egg \Goose egg\
In games, a zero; a score or record of naught; -- so named in allusion to the egglike outline of the zero sign 0. Called also duck egg. [Slang]
A bump on the skin caused by a blow, especially one on the head.
Usage examples of "duck egg".
Outside, duck egg-green shadows lay on the snow, the stars were brilliant in the clear, frosty night.
There was even a duck egg left over, half-buried in the weeds that the ducks had made into a nest.
The hard soil was covered with stones, mostly flat and about the size of a duck egg sliced the long way.
Her head tilted happily back, like a sparrow egg perched on a duck egg, she smiled into the sun.