Agrionius was an epithet of the Greek god

Greek mythology

Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...

 Dionysus

Dionysus

Dionysus was the god of the grape harvest, winemaking and wine, of ritual madness and ecstasy in Greek mythology. His name in Linear B tablets shows he was worshipped from c. 1500—1100 BC by Mycenean Greeks: other traces of Dionysian-type cult have been found in ancient Minoan Crete...

, under which he was worshiped at Orchomenus

Orchomenus

-Greek mythology:*Orchomenus, a king, the father of Elara*Orchomenus, one of the twenty sons of Lycaon*Orchomenus, son of Zeus and Isonoe, father of Minyas and Kyparissos*Orchomenus, a son of Athamas and Themisto-Ancient Greek geography:...

 in Boeotia

Boeotia

Boeotia, also spelled Beotia and Bœotia , is one of the regional units of Greece. It is part of the region of Central Greece. It was also a region of ancient Greece. Its capital is Livadeia, the second largest city being Thebes.-Geography:...

, and from which his festival, the Agrionia

Agrionia

Agrionia was an ancient Greek religious festival in honor of Dionysus Agrionius. It was celebrated annually, especially at Orchomenus in Boeotia....

, in that place derived its name. The epithet itself means "fierce", and is derived from a Greek root word indicating things relating to the wild. It is thought to represent Dionysus' fondness for savagery and savage beasts.