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.
Although the reservoir can be accessed via public footpaths, the owners installed barriers to prevent people from walking on the dam face, but these have been removed by trespassers.
From BBC ● Jul. 20, 2026
Twenty-six deaths were linked to a dam breach at Liulan Reservoir, with seven still missing there, state news agency Xinhua reported.
From Barron's ● Jul. 9, 2026
This question puts a crack in the dam, and in no time, a flood of emotional consequences follows.
From Salon ● Jul. 5, 2026
A wide river of cropped hair, crisp T-shirts, and adrenaline stretching almost 500 feet to Herndon, where they’re held back by an invisible dam about to burst.
From Slate ● Jun. 24, 2026
A moment later, Roz hauled herself out of the water and onto the dam.
From "The Wild Robot Protects" by Peter Brown
Earlier in July, local journalists were asked to "soften" their language to describe a major breach in the wall of the Liulan Dam near Naning as an "opening" or "gap".
From BBC ● Jul. 27, 2026
Denmark's Rikke Dam won the women's title with a time of 6:54:02 and Wang Shengxian of China won the men's race in 3:52:22.
From BBC ● Jul. 19, 2026
Commercial speculation is only one lobe of the American story; so too is public-spiritedness, of which there is no better example than Hoover Dam.
From The Wall Street Journal ● Jun. 27, 2026
That water helps replenish San Carlos Reservoir, which was created by the Coolidge Dam.
From Science Daily ● Jun. 18, 2026
When the St. Francis Dam first broke, their mother heard the sound of it and woke the girls' father.
From "100 Sideways Miles" by Andrew Smith
"We've now got probably about eight to ten smaller dams that have been built," Boles added.
From BBC ● Jul. 1, 2026
Patrolling has also reduced small-scale encroachments, but infrastructure projects including multiple dams are still driving deforestation.
From Barron's ● Jun. 25, 2026
Bolstered protections have helped slow both, though infrastructure projects, including dams, remain a serious threat.
From Barron's ● Jun. 25, 2026
Salmon numbers have declined due to dams, which have blocked off their spawning areas; the loss of floodplain habitat; and global warming, which is intensifying drought and heating rivers.
From Los Angeles Times ● May 21, 2026
Down the ravine, west of the hill above the springhouse, Harry had built three wonderful little dams.
From "Miracles on Maple Hill" by Virginia Sorensen
These lakes are prone to failing because they are precariously dammed by walls made of frozen earth, rocks and ice created by the movement of a glacier.
From The Wall Street Journal ● Apr. 1, 2026
Scientists have warned that Himalayan glaciers are melting because of climate change and creating glacial lakes, often dammed by loose rock and debris, which makes them unstable and prone to bursting their banks.
From BBC ● Aug. 16, 2024
Meadows along those dammed riverscapes have already acted as wildlife safety zones during several fires that burned through the reservation over the past few years, he said.
From Los Angeles Times ● Mar. 26, 2024
The process dirtied lakes, cut down forests and dammed up rivers.
From National Geographic ● Feb. 8, 2024
Orpheus, a professional architect, remodeled their house, designed and built a separate studio for Marian, and dammed up a small brook to make a swimming hole.
From "The Voice That Challenged a Nation: Marian Anderson and the Struggle for Equal Rights" by Russell Freedman
Growing up in rural Monmouthshire, she regularly got covered in mud and played for hours in the woods with her younger brother, damming rivers and making dens.
From BBC ● May 30, 2026
Andrew Law, a sociologist at Newcastle University in the U.K., has used lidar mapping to digitally preserve structures along China’s Yangtze River that were threatened or wiped out by extensive damming.
From Slate ● Jul. 25, 2025
Habitat destruction, damming, and pollution have decimated local populations, such that many species are in dire need of help.
From Science Daily ● Nov. 25, 2024
The last major on-stream reservoir project in the state was New Melones Lake, which came online in 1978 with the damming of the Stanislaus River.
From Los Angeles Times ● Nov. 21, 2023
They had more or less run amuck and were damming up rivers and flooding highways, filling pastures, even beginning to invade the cities.
From "Woodsong" by Gary Paulsen
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.
