In English, dam and weir can be used both for the bank that holds the water back, and the water that is held back. in the song "The Lambton Worm", the boy goes "fishing in the weir". In another song, "the miller was drowned in his dam",
   A fish weir is unusual, in that its main function is not hold the water back, but to let water through while holding the fish back.
   A good weir appears in the film "Kind Hearts and Coronets". Dennis Price is murdering all his relatives(all played by Alec Guiness) to get an inheritance. Hee kills one by unmooring the punt in which Alec Guiness is snogging his mistress on a dirty weekend by the Thames, and they both go over the weir and drown. Dennis Price stops himself feeling guity by saying "I was sorry to have to kill the girl as well, but I consoled myself by thinking she had already suffered a fate worse than death the night before".