Again, broadly speaking, over 30mph is a motorcycle, under 30mph is a moped (unless it's an ebike with pedal assist, but only in some states). It's complicated.
You used to see a lot of scooters (step-through motorcycles or mopeds) in California college towns but ebikes have decimated that market.
If you look at the "motorcycling countries" (SEA, India/Pakistan, Africa, Latin America, etc.), most terrible accidents happen because trucks share the road with an army of scooters. I've been to a few of them on a motorcycle and it's a nightmare. For the same reason, big cities in China introduced dedicated scooter lanes separated by concrete barriers.
But colloquially, if it’s a step-through, it’s called a scooter. Most of which have a CVT transmission, where most motorcycles have a 6-speed manual (toe shift) transmission.