Hi Carl,
I found this in one of my reference books. Hope it helps.
There are 4 modes (or roles) a wireless bridge can occupy.
1. Root Bridge can communicate with non-root bridges and clients. It can't communicate with another bridge setup as the root.
2. Non-Root bridge attaches to a root bridge. Some manufactures have a non-root mode that accepts clients as well. I think that slave mode might be the non-root bridge mode.
3. Access-Point Mode allows clients to attach.
4. Repeater- Used to extend the wireless range. Sits between a root bridge and a non-root bridge.