on line prepositional phrase 1on-line adjective 1on-line adverb 1 prepositional phrase1 •(US) In a queue; waiting one's turn for something.I'm waiting on line at the bakery.Get on line while I shop. on-line adjective1 •(old-fashioned) Dated form of online. on-line adverb1 •(old-fashioned) Dated form of online.
