Ghost or Spirit?

I don't know what we have at the library. There are so many definitions to ghost - as well as to spirit, that it can all be confusing.  What if we have BOTH!! At any rate, I found a few websites with some definitions of both that you might find interesting.

I like this one the best -
http://www.theastralworld.com/ghosts/types-of-ghosts.php

http://www.differencebetween.net/miscellaneous/difference-between-ghosts-and-spirits/

http://www.mystic-mouse.co.uk/Wisdom_Texts/Ghosts&Spirits.htm

http://www.keyway.ca/htm2003/20030524.htm

http://www.ehow.com/how_4716935_tell-spirits-ghost-communicating.html