Real Dictionary

dam
In the breeding of farm animals, an animal's dam is its mother.
countable noun: A dam is a wall that is built across a river in order to stop the water flowing and to make a lake.
verb: To dam a river means to build a dam across it.

dam in American English 1
a barrier built to hold back flowing water
to build a dam in
noun: a barrier to obstruct the flow of water, esp. one of earth, masonry, etc., built across a stream or river
transitive verb: to furnish with a dam; obstruct or confine with a dam

dam in American English 2
the female parent of any four-legged animal
noun: a female parent (used esp. of four-footed domestic animals)

dam in American English 3
abbreviation: dekameter; dekameters

Dam in British English
noun: ( Carl Peter) Henrik (ˈhɛnrəɡ ). 1895–1976, Danish biochemist who discovered vitamin K (1934): Nobel prize for physiology or medicine 1943

dam in British English 1
noun: a barrier of concrete, earth, etc, built across a river to create a body of water for a hydroelectric power station, domestic water supply, etc
verb: to obstruct or restrict by or as if by a dam

dam in British English 2
noun: the female parent of an animal, esp of domestic livestock

dam in British English 4
symbol for: decametre(s)