Definition of dam noun from the Oxford Advanced Learner's Dictionary

  1. 1a barrier that is built across a river in order to stop the water from flowing, used especially to make a reservoir (= a lake for storing water) or to produce electricity the Narmada dam in India The dam burst. Wordfinderbend, course, current, dam, downstream, estuary, river, source, tributary, waterfall See related entries: The power industry, Rivers and lakes, Mountains and valleys, Structures
  2. 2(specialist) the mother of some animals, especially horses compare sire
  3. 3= dental dam
  4. Word Originnoun sense 1 Middle English: from Middle Low German or Middle Dutch; related to Dutch dam and German Damm, also to Old English fordemman ‘close up’. noun sense 2 late Middle English (denoting a human mother): alteration of dame.Extra examples The dam burst and the valley was flooded. The dam has been breached and there is a danger of flooding. The dam holds back the water. a large hydroelectric dam on the Colorado River
See the Oxford Advanced American Dictionary entry: dam