Add-on and Surplus

Add-on noun - Something that is not necessary in itself but adds to the convenience or performance of the main piece of equipment.

Surplus and add-on are semantically related. In some cases you can use "Surplus" instead an adjective phrase "Add-on".

Surplus adjective - Being over what is needed.

Add-on and surplus are semantically related. Sometimes you can replace phrase "Add-on" with "Surplus", this terms are similar.

Nearby Word: surplusage