Definition - What does Plug-In mean?
A plug-in is an element of a software program that can be added to provide support for specific features or functionality.
Plug-ins are commonly used in Internet browsers but also can be utilized in numerous other types of applications.
Techopedia explains Plug-In
In general, plug-ins are part of an array of software components known as add-ons. Programs may be changed by different kinds of add-ons in different ways.
In popular technologies, like Internet browsers and audio/video applications, the ability to utilize plug-ins makes products more versatile and allows transparent and convenient customization according to the user's desired features. Plug-ins also can enable easier software upgrades or patches or additions by project collaborators. Plug-ins also can be a strategy for dealing with complex software licensing.
One plug-in example is the range of customizable options common with browsers like Mozilla Firefox. Users can download individual plug-ins for this free Web browser tool to promote different results on devices.