From older copaci (compare Aromanian/Meglenitic cupaci, Istro-Romanian copaț(“thicket, brushwood”)), probably a borrowing from Albaniankopaç(“treestump”) or less likely cognate to it as a Balkan substratum root. The current form was probably analogically formed as a singular from the earlier copaci, reinterpreted as a plural. Compare also Slavic kopati, which may be the ultimate origin of both the Romanian and Albanian.