What is 'OP'? I want to know the meaning of 'OP' used here?
OP stands for Original Poster/Original Post, which here is the person who asked the question or the question itself. In this case, it is you. In forums for instance, it is the person who starts the thread, or the first post in the thread.
I agree with the OP, acronyms can be very useful.
In video games, however, OP means "overpowered" - a person or group that is too powerful.
That class is too OP, everyone is gonna play it!