adj. 1. 1 (Computers) connected by a communications line to a computer. Opposite of off-line. Syn. -- online, on line(predicate). [ WordNet 1.5 ]
2. [ prenominal ] being in progress now; ongoing; as, on-line editorial projects. [ Colloq. ] Syn. -- in progress(predicate), ongoing, on line(predicate). [ WordNet 1.5 ]