What does dam mean?
A dam is a solid barrier erected across a river or stream to restrain its flow, most often forming a reservoir that supplies drinking water, irrigates farmland, controls flooding, or drives hydroelectric turbines. From ancient earth embankments to modern concrete arch structures like the Hoover Dam, these works rank among humanity's oldest and most consequential engineering feats, reshaping landscapes and entire regional economies. The word also carries a quieter, older meaning in animal husbandry: the dam is simply the mother of an offspring, especially among horses, cattle, and dogs, where pedigree matters. As a verb, to dam something is to block it up, literally or figuratively. Few words so compactly capture both monumental public infrastructure and intimate lineage — proof that even the plainest English words can carry remarkable range.
A barrier constructed across a river or stream to control or impound the flow of water.
"The new dam will provide hydroelectric power to three provinces."
Often paired with specific structural types: gravity dam, arch dam, embankment dam.
The female parent of an animal, particularly in breeding contexts.
"The foal traced its lineage to a prize-winning dam."
Chiefly used in livestock, equine, and veterinary registers.
To obstruct the flow of a body of water by constructing a barrier.
"They dammed the river to create a millpond."
Frequently appears in the phrase 'dam up'.
Standard regular plural; applies to all noun senses.
"The valley contains several large dams."
Beavers built dams millions of years before humans did — and one beaver dam in Canada stretches over half a mile long, visible from space.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dam
The noun 'dam' entered English in the late Middle Ages, borrowed from Middle Dutch or Middle Low German, where it denoted an earthwork barrier across water. Its Germanic relatives include modern Dutch 'dam' and German 'Damm', both retaining the same meaning. The word spread widely through engineering usage during the great canal- and reservoir-building eras of Europe and North America. The unrelated expletive 'damn' shares only coincidental spelling similarity, coming from Latin 'damnare'.
Related word forms
How dam is actually used
As a verb, 'dam' means to obstruct or hold back the flow of water, often phrased as 'to dam up'. The 'female parent' sense survives chiefly in breeding, livestock, and veterinary contexts and is largely unknown outside them.
Easily confused with dam
A dam is a physical barrier holding back water, while damn is an expletive used to express anger or condemnation.