not OnLine or on-line
The state of being connected to the Internet (generally through an ISP, an OSP, or a network). Used as an adjective, it describes a variety of activities that users do on the Internet, for example: online chat, online shopping, online games, online searching, online communities, and on and on. Note that some people think the word "online" in America Online should be spelled as "OnLine" since the "L" is part of the acronym in "AOL." However, the "L" in AOL is just there to make up a better acronym than simply "AO."
Editor's Note: NetLingo does not believe that online should be hyphenated (such as "on-line") due to the fact that in Internet lingo, the majority of words which are hyphenated (such as "e-commerce") are hyphenated because one of the terms is short for another word (in this case "e" is short for "electronic"). The term "online" was actually hyphenated in the beginning (circa 1995) but was quickly revised, and even though other lingo authorities (such as Webster's Dictionary) feel the term "online" should be hyphenated, there is no basis for including the hyphen, instead "on-line" is considered an outdated way of spelling it.
NetLingo Classification: Online Jargon