caupo.

Cognate with Ancient Greek κᾰ́πηλος (kắpēlos), possibly from Pre-Greek, likely borrowed separately. A derivation of either from Proto-Indo-European *kʷreyh₂- (“to buy”), whence ἐπρῐάμην (eprĭámēn) as suppletive aorist of ὠνέομαι (ōnéomai, “to buy”), seems far-fetched. As Beekes mentions, Furnee offers Hittite 𒄩𒀀𒀊𒈦 (ḫappar, “purchase, price”) as a comparandum, in which case the IE derivation would be *h₃ep-, whence ops (“power”) and Homeric Ancient Greek ἀφνειός (aphneiós, “rich, wealthy”), although this is also speculative. Gemoll considers a connection to Ancient Greek κάπτω (káptō, “gulp down, snap”).