Or pizmu. No definitive etymology can be suggested. Could be derived from
pasāmu ‘to cover up, to veiľ (AHw., Draffkorn Kilmer 1984:75, fn. 22). Alternatively (with Draffkorn Kilmer 1984:77, fn. 26), may be compared with Jewish Aramaic pzm (pa.) ‘to speak or sing in one’s turn’ (Jastrow 1150), Rabbinic Hbr. pizmōn ‘a poem with a refrain for congregational response’ (ibid.). Within this approach, pizmu could be of WS origin which would agree with its late attestation.