An Etymological Dictionary of the German Language/Annotated/Kupfer
Kupfer, neuter, ‘copper,’ from the equivalent Middle High German kupfer, Old High German chupfar, neuter; an old loan-word from which *kuppor must have been the earliest form; the word was borrowed before the 7th century; compare Dutch and Middle Low German koper, Anglo-Saxon copor, English copper, Scandinavian kopar. These are probably based on Middle Latin cuper (genitive -eris). Late Latin cuprum, or rather œs cyprium, or simply cyprium (whence French cuivre), is an Italian (not a Greek) term; the Teutons probably owe to the Italians their earliest knowledge of copper. The island of Cyprus was called Kipper by the Germans of the Middle Ages, following the Byzant. and Modern Greek pronunciation of Κύπρος; hence Middle High German kippor or kipperwîn, ‘Cyprian wine.’