In the phonetic alphabet, Uniform represents the letter U. My ever so reliable dictionary says that as an adjective, uniform means 1. always the same, unchanging. 2. consistent in appearance. As a noun: 1. a distinctive outfit intended to identify those who wear it as members of a specific group. 2. a single outfit of such apparel.
I don't know if any of you remember, but this is the outfit I pictured Hugh (a ghost from my novel GRIMOIRE) wearing - minus the sword. But he definitely had a hat like that he liked to remove with a flourish :)