Learn how to say Plugin correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word plug-in:
able to be connected by means of a plug:
a plug-in kettle
Computing (of a module or software) able to be added to a system to give extra features or functions:
a plug-in graphics card
1 Computing a plug-in module or plug-in software.
2Canadian an electric socket in a car park or garage for plugging in the block heater of a vehicle to prevent the engine from freezing.