arpatitu

Volscian

Unknown. Prefixed with ar-, Volscian cognate to of Latin ad-. The root underneath is uncertain:^[1]

Possibly from Proto-Indo-European *(s)kweh₁t- (“to shake”), cognate to Latin quatiō (via Proto-Italic *kʷatjō). Compare Ancient Greek ἐπιπάσσω (epipássō, “to sprinkle”).
Alternatively, it may derive from Proto-Indo-European *peth₂- (“to spread out”). If so, the term would be a cognate with Latin pateo (via a stative verb, Proto-Italic *patēō).

arpatitu (3rd person singular future active imperative)

^ Untermann, Jürgen (2000) “Vl. arpatitu”, in Wörterbuch des Oskisch-Umbrischen [Dictionary of Oscan-Umbrian] (Handbuch der italischen Dialekte; 3), Heidelberg: Winter, →ISBN, pages 120-121

2022, Blanca María Prósper, “The Tabula Veliterna: a sacred law from Central Italy”, in Rivista Italiana di Linguistica e dialettologia‎^[1], number XXIV (quotation in English; overall work in English), page 25:
1951, James W. Poultney, “Volscians and Umbrians”, in The American Journal of Philology‎^[2], volume 72, number 2, →DOI, →ISSN, page 117:
De Vaan, Michiel (2008) Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7)‎^[3], Leiden, Boston: Brill, →ISBN