The word comes from Islam and is meant to be a universal greeting. It's the only word I use to begin and end each communication with my fellow man. "Peace"--it's the prevention of conflict. "Peace"--it establishes both parties on a ground of mutual respect no matter who they are. "Peace"--it's universal. If an alien jumps in front of your ass, comes at you like "BLAAH!"--you can still say "Peace." He may even understand you.
     Peace. The whole energy of the word itself is good.
     Peace.
     But as they say, come in peace, but prepare for war.