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. (1998-12-22)
