Offline

The terms "online" and "offline" have specific meanings in regard to computer technology and telecommunications in which "online" indicates a state of connectivity, while "offline" indicates a disconnected state. Common vernacular extended from their computing and telecommunication meanings and refers specifically to an Internet connection. Lastly, in the area of human interaction and conversation, discussions taking place during a business meeting are "online", while issues that do not concern all participants of the meeting should be "taken offline"—continued outside of the meeting.

In computer technology and telecommunication, online and offline are defined by Federal Standard 1037C. They are states or conditions of a "device or equipment" or of a "functional unit". To be considered online, one of the following may apply to a system: it is under the direct control of another device; it is under the direct control of the system with which it is associated; or it is available for immediate use on demand by the system without human intervention.

In contrast, a device that is offline meets none of these criteria (e.g., its main power source is disconnected or turned off, or it is off-power).

The Oxford dictionary defines "online" (sometimes also referenced as "On the Line") as "controlled by or connected to a computer" and as an activity or service which is "available on or performed using the Internet or other computer network". The term is utilized within terms such as these: "online identity", "online predator", "online gambling", "online shopping", "online banking", and "online learning". The online context is given to other words by the prefixes "cyber" and "e", as in the words "cyberspace", "cybercrime", "email", and "ecommerce".

...
Wikipedia