What really is the Holy Ghost?

I want to be clear here I am a faithful member who is very active and studies all the time. I know the doctrine and great and powerful effects and uses of the Holy Ghost. I know how to recognize it and seek to follow where I can.

this is not any of those questions. I mean what is the Holy Ghost really? we know Heavenly Father and Jesus Christ are divine exalted of our kind but almost nothing as to what the Holy Ghost is. I have heard the thought that it may be the Father's spirit but I don't know how much I like that thought as it's almost binatarien.