IO

IO may refer to:

An abbreviation

* I.O., a theater in Chicago, Illinois dedicated to improvisational comedy
* Industrial organization, the field of economics that studies the strategic behavior of firms, the structure of markets and their interactions
* Input/output, the collection of interfaces that different functional units of an information processing system use to communicate with each other
* International Operations, a fictional American Intelligence Agency in Wildstorm comics
* "International Organization", a peer-reviewed journal that covers the entire field of international affairs
* Intraosseous infusion, the medical process of introducing medication directly into the bone marrow.
* IO Interactive, a Danish computer game developer
* iO Digital Cable, a service offered by Cablevision.
* Investigating Officer, a police officer usually from CID but of any rank, who heads an investigation
* Interest Only, a type of Collateralized Mortgage Obligation(CMO)

A code

* Indonesian Airlines' IATA airline designator
* British Indian Ocean Territory's ISO 3166-1 alpha-2 country code and DAFIF 0413 / DIA 65-18 / FIPS PUB 10-4 territory code.
* The ISO two-letter code for the constructed language Ido.

In astronomy

* Io (moon), a moon of Jupiter

In Literature

* Blind Io, the King of the Gods in the Discworld series of novels by Terry Pratchett

ee also

* io
* .io
* I/O (disambiguation)