Kind of a 'war of words', depending on what part of the world you live in...
to me, in Canada,eh...
dynamo, is a device with a rotating magnet and a fixed coil that produces power
generator, a device with a powered field coil, brushed making DC power
alternator, a device with a powered field coil,brushes making AC power
in the 'grand scheme of things' ,dynamos are simple cheap and fewest problems. Aside from bearings( common to all) , not much can fail. electrically only one component the 'coil'.