Jono @16, the definition in Chambers should have been more clear. The word in question is essentially synonymous with level. Some say degree. For example, I am a first degree black belt (or first ___ ) in taekwondo. While I am not as familiar with judo, I believe the same idea applies. You wouldn't use the word alone to refer to the person, just like you wouldn't call that person a degree or level; it would always have to have the preceding ordinal number.
I still can't find anything in the Chambers app for how 11 relates to soldiers. Can you point me in the right direction?