Magnesia

Magnesia may refer to:

a Greek toponym, derived from the tribal name Magnetes
  • Magnesia (regional unit), the southeastern area of Thessaly in central Greece
  • Magnesia ad Sipylum, a city of Lydia
  • Magnesia on the Maeander, an ancient Greek city in Anatolia
  • Magnesia Prefecture, a former prefecture of Greece
  • Magnesia, a mythical city-state in Plato's Laws
in chemistry
  • Magnesium oxide
    • Periclase or magnesia, a natural mineral of magnesium oxide