by DaddyO
Here is how I classify the often misunderstood differences between the two:
Top/bottom = Roles in a scene (or play partnership). No emphasis on power exchange unless negotiated otherwise. Both Top and/or bottom can make decisions.
Dom/sub = Roles in power exchange (most usually in a relationship). And the "relationship" could be as short as a single scene or as long as a lifetime partnership. Dom makes the decisions after sub sets the parameters and gives over control.