a barrier to obstruct the flow of water, especially one of earth, masonry, etc., built across a stream or river.
a body of water confined by a dam.
any barrier resembling a dam.
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
a reservoir of water created by such a barrier
something that resembles or functions as a dam
1275–1325; Middle English < Middle Dutch, Middle Low German, dam; akin to Old English for-demman to stop up, block
1250–1300; Middle English; variant of dame
A barrier built to block the flow of water is called a dam. If you walk along a stream, you can see where beavers have built a dam out of mud and logs. As a verb, dam means to obstruct or blockade as with a dam. If the kids you're babysitting dam up the bathtub drain when you're not paying attention, the water might overflow and cause a waterfall into the living room downstairs. But water isn't the only thing that can be dammed. You shouldn't dam up your emotions — go ahead and scream if you need to.
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Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Riddle asked the Bureau of Reclamation to revise the plan so the water that’s released from the dam stays cold enough for salmon.
From Los Angeles Times • May 21, 2026
The researchers also examined how river flow patterns and dam impoundment affect oxygen decline.
From Science Daily • May 17, 2026
McInnes tried to be measured but the dam burst a little when he spoke about the decisions he feels are going against his club.
From BBC • May 14, 2026
Federal Court judge Stephen Burley described how four large open-pit mines, a railway, tailings dam, waste dumps and a stockpile were strewn across the lands of the Yindjibarndi people in Western Australia's Pilbara region.
From Barron's • May 12, 2026
Farmer didn’t dare go back by the same route, on foot over the dam.
From "Mountains Beyond Mountains" by Tracy Kidder and Michael French
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
