Old English paþ, pæþ "path, track," from West Germanic *patha- (source also of Old Frisian path, Middle Dutch pat, Dutch pad, Old High German pfad, German Pfad "path"), of uncertain origin. The original initial -p- in a Germanic word is an etymological puzzle. Don Ringe ("From Proto-Indo-European to Proto-Germanic," Oxford 2006) describes it as "An obvious loan from Iranian ..., clearly borrowed after Grimm's Law had run its course." Watkins says the word is "probably borrowed (? via Scythian) from Iranian *path-," from PIE root *pent- "to tread, go, pass" (source of Avestan patha "way;" see find (v.)), but this is too much of a stretch for OED and others. In Scotland and Northern England, commonly a steep ascent of a hill or in a road.