No definitive etymology can be proposed.
The variant maskiltu (CAD, CDA) is due to a misreading (von Soden 1982, 590). No etymology can be suggested.
The Akk. mathematical term basû is a loanword from the Sum. verbal form ba-SI/SI₈(-e) which can be used as a noun in mathematical texts.
Derived words: bāṣiru (a class of people) (AHw. 1547, CDA 40).
Derived words: biṣṣu 'trickle' (CAD B 268, 269, AHw. 130, 131, 1548); buṣāṣu 'trifles' (CAD B 348, AHw. 883).
Probably related to either Arb. bḍḍ 'to flow by little and little' or Arb. baṣṣa l-māˀu = rašaḥa “to leak, to ooze (of water)” (TA 17 491).
The Aramaic etymology proposed in AHw. 1547 seems doubtful, since, as rightly observed in Abraham-Sokoloff 2011:28, the Aramaic lexeme biṣˁā to which von Soden refers does not exist. What he likely means is Rabbinic Hebrew biṣˁā, translated as “ditch, dike, pond” in DTTM 184. The marginal attestation of this word and the semantic difference between it and the Akkadian lexeme in question makes von Soden's comparison rather unlikely.
No etymology can be suggested.
Or baṣṣu. Cf. bāṣiš 'like sand' (CAD B 134, AHw. 110).
The Akkadian lexeme has been compared to Hbr. bōṣ 'silt'.
No etymology can be suggested.