What is Duck ?
Duck is (noun) 1. a common water bird Let’s go and feed the ducks in St James’ Park. water (NOTE: The male is a drake, the female a duck and the young are ducklings.) 2. the meat of this bird We’re having roast duck for dinner. 3. (in cricket) a score of zero He scored a duck in his last two matches. (verb) to lower your head quickly to avoid hitting something She didn’t duck in time and the ball hit her on the head. He ducked as he went through the low doorway.
source: Easier English, Student Dictionary Upper Intermediate Level