If something is online, it means a computer can access it, usually over the internet or a network. It might be a website or a searchable database.

It might also be online through a specific network, like our computer labs - the library has some CD-ROMs that are mounted on the network and available online. Find them under "Library Resources" when you're logged into the network.

Anything that is online must be electronic or digital, so that a computer can read it.

But everything that's electronic isn't necessarily online.

The term online refers more to the availability or location of the item than the format.