Why Holy Ghost?
I think the word "Ghost" is corney and in accurrate! What is he a Ghost of?
It's is more accurate to say "Spirit" for that is what is accurately depicted in the scriptures (Original Language).
The Hebrew calls him qodesh {ko'-desh} ruwach {roo'-akh} or Holy Spirit!
The Greek calls him hagios {hag'-ee-os} pneuma {pnyoo'-mah}.