Io

Io, in astronomy, one of the 39 known moons, or natural satellites, of Jupiter. Io is subject to Jupiter's enormous tidal forces and is, as a result, the most volcanically active body in the solar system.

Io, in Greek mythology, daughter of Inachus, king of Argos. She was loved by Zeus, who, to protect her from Hera's jealousy, changed her into a white heifer. Hera, however, was not deceived; she claimed the heifer and sent Argus to guard it. When Hermes killed Argus, Hera tormented Io with a gadfly which drove her across Europe and through Asia, until she was finally allowed to rest in Egypt. There Zeus returned her to human form, and she bore his child Epaphus. Io has been identified with the Egyptian goddess Isis.

In Greek mythology, the daughter of the river god Argos. Io drew Hera's jealousy when Zeus fell in love with her. Zeus changed her into a white heifer to protect her. Hera sent the many-eyed creature Argus to watch over the heifer, but Zeus sent Hermes to lull Argus to sleep and kill him. Hera then sent a gadfly to pursue Io, who fled across Europe and crossed the bodies of water later named the Ionian Sea and the Bosporus (“Ford of the Cow”) in her honour. When she arrived in Egypt she resumed her original form. She was later identified with the Egyptian goddess Isis.

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Io or io may refer to:

• Io (mythology), daughter of Inachus in Greek mythology
• Io (moon), a moon of Jupiter
• Io Matua Kore, in some Māori traditions the supreme god
• 85 Io, an asteroid
• Io (gastropod) a genus of freshwater snail in the family Pleuroceridae
• The Hawaiian Hawk's local name
• Io (voievodal title particle), a particle of a title used by Romanian royalty from Moldavia and Walachia
• Iwo Jima, a volcanic island in Japan

In modern fiction:

• Blind Io, the current king of the gods in Terry Pratchett's Discworld series of fantasy novels
• Io (Dungeons & Dragons), the chief deity worshipped by dragons in the Dungeons & Dragons role-playing game
• Io (Babylon 5), a space station in the science fiction television show Babylon 5

In technology:

• The IO.SYS file in DOS and Windows 95, 98 and ME.
• Io (programming language), a pure object-oriented programming language
• iO Digital Cable Service, a digital cable service offered by Cablevision
• Mitsubishi Pajero iO, a mini SUV produced by Mitsubishi Motors
• Input/Output, communication between information processing systems

See also

• IO
• .io
• IiO
• ImprovOlympic