io

Noun (1)

io (plural ios)

1. A type of moth, the io moth.
   • These lines appear to serve as roadways or guides to any stragglers that may have hung back for some reason known only to an io.1936, Paul Griswold Howes, Hand book for the curious

Interjection

1. (rare) An exclamation of joy or triumph.
   • Do as thou wilt, as a great god can,
     O Pan! Io Pan!
     Io Pan! Io Pan Pan! I am awake
     In the grip of the snake.1913, Crowley, Aleister, “Hymn To Pan”, in Book 4, University of California Libraries, Magick in Theory and Practice

Noun (2) capitalized: IO

IO (countable and uncountable, plural IOs)

1. (abbreviation, initialism) Initialism of input and output.
2. (abbreviation, initialism) Initialism of indirect object.
3. (abbreviation, initialism) Initialism of intelligence officer.
4. (abbreviation, initialism) Initialism of incident officer.
5. (Singapore, abbreviation, initialism) Initialism of investigation officer.
6. (abbreviation, initialism, international law) Initialism of international organization.

Adjective capitalized: IO

IO

1. (abbreviation) Abbreviation of intraosseous.

Proper noun capitalized: Io

Io

1. (Greek) The daughter of Inachus river god, and a lover of Zeus, turned by the latter into a heifer.
2. A moon of Jupiter, known for its volcanic activity, peppered with about 400 active volcanoes.
   • A mottled blanket of debris from many active volcanoes gives Io the youngest surface in the solar system.1990 August, Bradford A. Smith, “Voyage of the Century”, in National Geographic, volume 178, number 2, page 50
   • Another whisper, sir, near Io. We have probes en route.2004 November 9, Bungie, Halo 2, spoken by Cortana (Jen Taylor), Microsoft Game Studios, Xbox, level/area: Cairo Station
3. 85 Io, a main belt asteroid; the asteroid shares its name with the Jovian moon