This word is traditionally derived from Proto-Baltic *per-k-, *pr̥k-, from Proto-Indo-European *per- (“taking over, past something”) (whence Latvian prepositions par, pār, q.v.), as a verb “to take over, past (somewhere)” > “to take (somewhere) to sell” > “to sell”, with an extra k. With this meaning, cf. Ancient Greek περνάναι (pernánai), πιπράσκειν (pipráskein, “to sell, to export”), and Old Irish renim (“I sell”) (< *pr̥-nā-). In the Baltic languages, the meaning “to sell” became “to buy,” given the nature of buying and selling as two aspects of the same two-sided event. From the same stem also prece (“product, ware, merchandise”), q.v. A more recent suggestion is that pirkt may derive from another Proto-Indo-European stem *per- (“to hit”) (whence pērkons (“thunder”), q.v.), with as original meaning “to rob, to plunder;” in several Indo-European languages, verbs of buying originate from verbs of taking (cf. Latin emere (“to buy”), earlier “to take”). Cognates include Lithuanian pir̃kti.