For non-bikers, a scooter has an automated gearbox and small wheels etc. Think vespa.
In the UK at least they are generally a different category of license, although that's because of the size of a standard scooter engine.
> A scooter (motor scooter) is a motorcycle with an underbone or step-through frame, ....
Scooters are often legally motorcycles as well. For example, I had to get a motorcycle endorsement on my license for a scooter I owned, because the engine displacement was too large for the extremely restrictive "moped" category in my state.
There's motorbikes with scooter like controls, there's scooters with motorbike like controls. Many small automatic motorbikes feel basically identical to driving a scooter except that your sitting position is very slightly different.
I'm a big fan of two-wheeled transport in all its forms, but wow is there a prevailing toxic attitude among a large group of "true motorcycle" riders. Instead of welcoming people into the fold, it's just tribalism -- you drive a scooter, you're not a true biker; you ride a cruiser, true bikers only drive super sports; you drive an e-bike, but only loud pipes make a true rider!
I actually feel a fellowship with all two-wheel riders but don't let any other bikers know or I'll be shunned.
Scooters are cycles that have motors, and are thus motorcycles in the most-inclusive definition of such.
Reminds me of this scene from Police Academy 3: https://www.youtube.com/watch?v=cil6HFXlccw