Boy takes the derogatory name to subvert it. Instead of a slave who is dependent upon the Mastah, she is independent and fights for freedom. It's interesting to note how she losses her independence and almost becomes the Archon's "boy" during American Death Camp.
Wow, the only two black characters in the story and they both take on the masters names for them in order to 'subvert' them. Gosh, what a radical genius Morrison is- sorry, forgetting my place there for a minute.