Add-on and Protuberance

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

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

Protuberance noun - A part that sticks out from the general mass of something.

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

Nearby Word: protuberant