Dacia was bounded in the south approximately by the Danubius river (Danube), in Greek sources the Istros, or at its greatest extent, by the Haemus Mons (the Balkan Mountains). Moesia (Dobrogea), a region south of the Danube, was a core area where the Getae lived and interacted with the Ancient Greeks. In the east it was bounded by the Pontus Euxinus (Black Sea) and the river Danastris (Dniester), in Greek sources the Tyras. But several Dacian settlements are recorded between the rivers Dniester and Hypanis (Bug River), and the Tisia (Tisza) to the west.
The Dacians were known as Geta (plural Getae) in Ancient Greek writings, and as Dacus (plural Daci) or Getae in Roman documents; also as Dagae and Gaete—see the late Roman map Tabula Peutingeriana. It was Herodotus who first used the ethnonym Getae. In Greek and Latin, in the writings of Caesar, Strabo and Pliny the Elder, the people became known as ‘the Dacians’.
The name Daci, Daki, or "Dacians" is a collective ethnonym. Dio Cassius reported that the Dacians themselves used that name, and the Romans so called them, while the Greeks called them Getae.
Romanian historian of religions Mircea Eliade attempted, in his book From Zalmoxis to Genghis Khan, to give a mythological foundation to an alleged special relation between "Dacians and the wolves"
Dacians might have called themselves "wolves" or "ones the same with wolves",
Dacians draw their name from a god or a legendary ancestor who appeared as a wolf
Dacians had taken their name from a group of fugitive immigrants arrived from other regions or from their own young outlaws, who acted similarly to the wolves circling villages and living from looting. As was the case in other societies, those young members of the community went through an initiation, perhaps up to a year, during which they lived as a "wolf".