|online or on-line (ˈɒnˌlaɪn)|
|1.||of, relating to, or concerned with a peripheral device that is directly connected to and controlled by the central processing unit of a computer|
|2.||of or relating to the internet: online shopping|
|3.||occurring as part of, or involving, a continuous sequence of operations, such as a production line|
|4.||while connected to a computer or the internet|
|on-line or on-line|
1. Ready for use. E.g. "The graph plotter's fixed and on-line again".
2. Interactive as opposed to batch. Accessible via a computer (or terminal), rather than on paper or other medium.
3. Of a user, actively using a computer system, especially the Internet. E.g "I haven't been on-line for three days."
"On-line" should be hyphenated because it is compounded from two words but the hyphen is often omitted in names of organisations or services.