From Old Norse sléttr, from Proto-Germanic *slihtaz (“slippery, flat, level, plain”). Cognate with Swedish slät (“smooth”), English slight, Scots slicht (“bad, of poor quality”), West Frisian sljocht (“smooth, level, plain, simple”), Dutch slecht (“bad”), Low German slecht (“bad”), German schlecht (“bad”) and schlicht (“plain, artless, natural”), Danish slet (“bad, evil, poor, nasty, wrong”), Norwegian slett (“even”), Icelandic sléttur (“even, smooth, level”).