Plug-in and Plug-in unit

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

Plug-in unit and plug-in are semantically related. In some cases you can replace phrase "Plug-in unit" with "Plug-in", this phrases are similar.

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