διφθέρα (diphthera)

1. a prepared hide, tanned skin, piece of leather , (Herdotus Historicus); opposite to δέρρις (an undressed hide) , (Thucydides):—; διφθέραι were used for writing-material in ancient times, before papyrus came in, (Herdotus Historicus)
2. a leathern garment such as peasants wore, (Aristophanes Comicus)
3. a wallet, bag , (Xenophon Historicus)
4. in plural skins used as tents , (Xenophon Historicus) (ML)