All bicycle flats are just that - flats. A high pressure tyre might go with a bit of a pop, due to that high pressure, but it's still just a puncture.
A blow out by definition happens to a partially deflated tyre and is due to the friction caused by the sidewall of the tyre rubbing on itself and the rim. This friction in turn causes heat build up and the tyre then fails in spectacular fashion. It's very rare for this to happen on a car and wouldn't happen on a bike, due to a) the rider seeing/feeling the deflation and
not going fast enough for the heat build-up.
People tend to use the term for any puncture that happens at a high speed or makes a loud noise, but they're wrong!
Here endeth todays lesson.