From Middle English rode, rood (“cross”), from Old English rōd (“cross”), from Proto-Germanic *rōdō, *rōdǭ (“rod, pole”), from Proto-Indo-European *rōt-, *reh₁t- (“bar, beam, stem”).
Cognate with German Rute (“rod, cane, pole”), Norwegian roda (“rod”). Largely displaced by cross. More at rod.