Online may refer to any of the following:
1. Today, being online refers to when a user, computer, or another device is connected to the Internet.
Should I use "online," "on-line," or "on line" in my writing?
2. When referring to a hardware device, online is a description of when a connection has been made with another device or service. When a device is online, it can send or receive information from the other end of the connection. For example, if your printer is online, you should be able to print anything on the printer. If the printer is offline, you would not be able to print.
3. Online gaming describes a player who is connected to a server and is playing with other real people from around the world. Online gaming requires that the user has an active connection to the Internet or another service that allows them to connect to the server and see all other players.