1. something that has been or can be added to an existing object or arrangement: "cars with add-on extras"
▪ an accessory device or piece of software designed to increase the capability of a computer or hi-fi system: "now you can get the incredible sound of compact disc without getting an add-on amplifier"
▪ a unit of construction added to an existing construction:"the new kitchen replaces an add-on that was torn down in 1980"
