Quiz: Remember the definition of mal de mer?
"wet, swampy tract," 1650s, from Dutch moeras "marsh, fen," from Middle Dutch marasch, from Old French marais "marsh," from Frankish, possibly from West Germanic *marisk, from Proto-Germanic *mariskaz "like a lake," from *mari "sea" (see mere (n.)). The word was influenced in Dutch by moer "moor" (see moor (n.)). Figurative use is attested from 1867. Replaced earlier mareis (early 14c.; see marish).