Plug-in and Plug into

Plug-in noun - A printed circuit that can be inserted into expansion slots in a computer to increase the computer's capabilities.

Plug into and plug-in are semantically related. In some cases you can use "Plug into" instead a verb phrase "Plug-in".

Plug into verb - Plug into an outlet.

Plug-in and plug into are semantically related. Sometimes you can replace phrase "Plug-in" with "Plug into", this terms are similar.