Adjective

1. Describes a system which is connected (generally electrically) to a larger network.
   1. Describes a generator or power plant which is connected to the grid.
   2. Describes a computer which is connected to the Internet or to some other communications service.

      Is this modem online?

2. Available over the Internet.

   I prefer to read the online newspapers.

3. Available on a computer system, even if not networked.

   Press the F1 key to access the online help.

Adverb

1. Describes actions performed over the internet.

   He works online.