Io

Io, IO, iO, I/O, i/o, or i.o. may refer to:

Iowa ( (listen)) is a state in the Midwestern United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west.

iOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc. exclusively for its hardware.

iOS is a mobile operating system, developed by Apple Inc. for iPhone, iPad, and iPod Touch. Updates for iOS are released through the iTunes software and, since iOS 5, via over-the-air software updates.

iOS jailbreaking is privilege escalation for the purpose of removing software restrictions imposed by Apple on iOS, tvOS and watchOS.

Iowa State University of Science and Technology, generally referred to as Iowa State, is a public land-grant and space-grant research university located in Ames, Iowa, United States.

Ionizing radiation (ionising radiation) is radiation that carries enough energy to knock electrons from atoms or molecules, thereby ionizing them.

An ion thruster or ion drive is a form of electric propulsion used for spacecraft propulsion. It creates thrust by accelerating positive ions with electricity.