- an ancient district in S Greece, on the Gulf of Corinth.
- a department of Greece, in the N Peloponnese. Capital: Patras. Pop: 318 928 (2001). Area: 3209 sq km (1239 sq miles)Modern Greek name: Akhaïa
- a province of ancient Greece, in the N Peloponnese on the Gulf of Corinth: enlarged as a Roman province in 27 bc