dam

Pluraldams

Formsdams, damming, dammed

1. 1
   river barriernouncountable

   A barrier built across a flowing body of water to stop or divert the flow, often to store water or prevent sudden flooding.

   The dam regulates the river's flow to protect downstream towns from flooding.

   Workers reinforced the aging dam after engineers found cracks in its concrete.

   Usagedam sounds like damn. You build a dam across a river, and water is held behind the dam.

   Similarbarrage

   Note

   The engineering sense at the root of all the water words. Rivers are harnessed by dams, not merely blocked. Several unrelated words share the spelling. The breeder's word for a mother comes from dame, and another dam is simply damn written as it is said. Source

   Checked 3 Nov 2026 · 4 facts

   • The water-related senses of dam derive from the barrier sense. en.wiktionary.org
   • Dams harness rivers for useful purposes. en.wikipedia.org
   • Dam has unrelated homonyms; the animal-mother word derives from dame. en.wiktionary.org
   • Dam is also a pronunciation spelling of damn. en.wiktionary.org
2. 2
   block waterverbtransitive

   To block or restrict the flow of water by placing a barrier across it.

   The settlers dammed the creek to power their mill.

   Engineers plan to dam the river upstream of the town.

   UsageForms are dammed (which sounds like damned) and damming. Often dam up a stream.

   Similarblock, obstruct

   Note

   In Thomas Otway's Venice Preserv'd (1682), a man's doors are "fill'd and damm'd up with gaping creditors," blocked by people rather than a river. Source

   Checked 1 Nov 2026 · 2 facts

   • Thomas Otway wrote Venice Preserv'd, first published in 1682, as confirmed by its first-edition title page. en.wikisource.org
   • In Act I, Jaffeir describes his doors as filled and blocked by creditors; the quoted wording is accurate apart from capitalization. en.wikisource.org
3. 3
   animal mothernouncountable

   The female parent of an animal, especially in the context of breeding livestock or pets.

   The puppy inherited its calm temperament from its dam.

   Each calf is recorded alongside its dam and sire in the herd book.

   UsageMostly breeders' talk, paired with sire for the father.

   Similarmother

   Oppositesire

   Note

   A breeder's word: a variant of dame and a doublet of domina and donna, so a foal's mother shares a family with the lady of the house. Its partner is sire. Byron's Don Juan (1819) jokes that the hero's "sire was of Castile, his dam from Aragon," putting stud-book language to a human pedigree. Spenser and Shakespeare use it tenderly, of animals and their young. Source

   Checked 30 Oct 2026 · 7 facts

   • The animal-parent word dam is a variant of dame and a doublet of domina and donna. en.wiktionary.org
   • The word's ancestry connects it with a word meaning mistress of the house. en.wiktionary.org
   • Sire is the corresponding term for the male parent. en.wiktionary.org
   • Don Juan first appeared in 1819, when its first two cantos were published. nls.uk
   • Byron's narrator humorously describes Juan's human pedigree with the quoted animal-breeding terms. gutenberg.org
   • Spenser uses dam in an affectionate comparison involving animals and their young. gutenberg.org
   • Shakespeare uses dam sympathetically for an animal mother; King Henry speaks the passage in Henry VI, Part 2. gutenberg.org
4. 4
   reservoirnouncountable

   The body of water held back by a dam; in Australia and South Africa, any reservoir or pond built to store water.

   After months without rain, the water level in the town's dam has dropped below thirty percent.

   After heavy rains, the dam rose to its highest level in years.

   Similarreservoir

5. 5
   dentistrynouncountable

   A thin sheet of latex or similar material, anchored by a clamp around the tooth, that isolates a tooth and keeps it dry during dental work.

   The hygienist secured the dam before the procedure began.

   Dental dams reduce contamination by saliva during restorative work.

   UsageUsually dental dam or rubber dam, unless the setting makes it clear.

   Note

   Dentistry borrows the river word for this rubber sheet. It does for saliva what the barrier across a river does for water, holding it back so the work stays dry. A small clamp fitted around the tooth anchors the sheet. Outside the clinic, a dental dam also means a sheet of this kind used as a barrier during oral sex to lower the risk of infection. Source

   Checked 1 Nov 2026 · 5 facts

   • The dental sense is a transferred use of the water-barrier noun; Wiktionary groups both under the same etymology. en.wiktionary.org
   • The sheet excludes moisture from the dental working area. dpes.dentistry.utoronto.ca
   • A clamp around the tooth stabilizes the sheet. en.wikipedia.org
   • Dental dams are also sheets used as barriers during oral sex. cdc.gov
   • Using a dental dam during oral sex can lower infection risk. cdc.gov

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