First attested as wesepe in 1284. Etymology uncertain. Potentially a compound of either Proto-Germanic *wese- (“pasture”) or *wisi- (“good”) and *apa (“river, current”). A derivation from Proto-Indo-European *wis- (“flow, flow away”) or *weis- is also possible. Compare Weesp, Wesepe and Wezep. See also Dutch Low Saxon Wisp.