arbiter \AR-buh-tuhr\, noun:
1. A person appointed or chosen to judge or decide a dispute.
2. Any person who has the power of judging and determining.
Here's an image with some of the concept rank names discussed in this thread, as well as the rank symbols. Rank symbols are much like stripes and bars used by the military to signify rank. Plus they just look cool :O
Look Here:
http://www.fallenangelsx.com/images/ranksymbols2.jpg