Add-on may refer to the following:
1. A software add-on or extension is any third-party software program or script that is added to a program to give it additional features and abilities.
For example, Adobe Flash, which allowed users to watch videos or play games within an Internet browser, is an excellent example of a software add-on.
Add-ons are often created by people or organizations not affiliated with the original developer and installed using a program option or through a third-party website.
2. When referring to hardware, an add-on is any component that enhances the capabilities or performance of your computer. For example, additional RAM, a new CPU, or a faster video card could all be considered add-ons.