Simple past tense and past participle of dam.(verb)
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Use "dammed" in a sentence
"Winthrop, as well as in the records of the colonies, evidence which shows that the streams of wickedness in New England were "dammed" and not dried up."
"Quit being so dammed mamsey pamsey and PC about everything."
"The upshot of my research is that the design basis of envelopes of the aircraft and of other structures in general - like railways and metro bridges are beginning to be exceeded with significant frequency due to excessive instantaneous cumulative electrical load demand being placed on hydrogenerators occurring in heavily dammed regions."