Or piṣallūru. Fem. pizallurtu, in Mari pišḫallurtu. 
No definitive etymology can be suggested. Cf. 
*pVṣγ-’gecko’, even if the by-form pišḫa- does not readily support this equation: while ḫ may indeed reflect (or render) *ġ, Akk. š does not regularly correspond to *ṣ. At any rate, the latter part of the Akkadian lexeme (-llūru) remains diachronically obscure.