Add-on and Pullout

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

Pullout and add-on are semantically related. In some cases you can use "Pullout" instead a noun phrase "Add-on".

Pullout noun - An act of moving away especially from something difficult, dangerous, or disagreeable.

Add-on and pullout are semantically related. Sometimes you can use "Add-on" instead a noun "Pullout".