What is "hercuniates"

Hercuniates were a Celtic tribe that migrated to Pannonia in Illyria. By the middle of the first century BC, the Hercuniates were a minor tribe that was located along a narrow band of Celtic settlement close to the Danube, on the western side of the river a little way west of modern Budapest. Their name comes from an ancient proto-Indo-European word for an oak. The tribe is referred to by Pliny and Ptolemy as a civitas peregrina, a wandering tribe that had travelled to Pannonia from foreign parts. Little else is known of them save that they were issuing their own coins by the second century BC. By AD 40 the tribe was eventually subdued by Rome.