Dictionary of Business Terms: online
online
connected to a computer, network, or host, especially to the Internet; contrast with offline. A user may consult online Help (application documentation in searchable form stored in the computer) or "go online" to check e-mail.
Dictionary of Computer and Internet Terms: online
online
connected to a computer or available through a computer. For example, online help is information that can be called up immediately on a computer screen rather than having to be looked up in a book.
In New York City but not elsewhere, on line means "in a queue," as in We are standing on line - the rest of the country says standing in line. In this context it is not a computer term and is not written as a single word.
