The use for a vessel is exclusively Luxembourgish (in the Rheinisches Wörterbuch only given for the border village of Körperich). A more widespread sense is an instrument for hitting, which also occurs in Luxembourgish Uessebiz (“pizzle”). This is either from Dutch pees (cf. bullenpees) or rather a derivative of Middle High German bōzen (“to hit”). However, it is difficult to connect the two meanings. Thus alternatively perhaps comparable to regional German Bietz (“breast, mamma”) and further possibly from Old French piz (“udder”). The semantic connection in this case may be a spouted drinking vessel for children, but this is speculative. (This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)