-- A motor and a generator both do a transformation between electrical energy and some other form of energy, but they do it in opposite directions.
-- A motor takes electrical energy and transforms it into mechanical energy, which can then be used to run mechanical things like cars or wheat grinders.
-- A generator takes mechanical energy ... like from a steam turbine or a windmill or a water wheel ... and transforms it into electrical energy, which can then be shipped over long distances through wires, and used to run motors or other electrical things.