"small puddle, shallow pool, wet ground," Old English plæsc "pool of water, puddle," probably imitative (compare plash (v.1) and Dutch plass "pool"). Meaning "noise made by splashing" is recorded by 1510s. Related: Plashy.
capital of Ireland, literally "black pool," from Irish dubh "black" + linn "pool." In reference to the dark waters of the River Liffey. Related: Dubliner.
1890, a New Englandish word for "swimming pool, place for swimming," from Late Latin natatorium, from Latin natator "swimmer" (from nare "to swim") + -ium, neuter suffix. Latin nare is from PIE root *sna- "to swim." Middle English had natatorie "a pool, bath," early 14c., from Latin.
"pool, small lake, pond," from Old English mere "sea, ocean; lake, pool, pond, cistern," from Proto-Germanic *mari (source also of Old Norse marr, Old Saxon meri "sea," Middle Dutch maer, Dutch meer "lake, sea, pool," Old High German mari, German Meer "sea," Gothic marei "sea," mari-saiws "lake"), from PIE root *mori- "body of water." The larger sense of "sea, arm of the sea" has been obsolete since Middle English. Century Dictionary reports it "Not used in the U.S. except artificially in some local names, in imitation of British names."