Well that's exactly my point.

Also you say "characterise"... when measure is the correct word.
Because we measure velocity not jut by mathematical systems but with ACTUAL mechanical systems. It's one part of science which is the most studied.

Particle Physics.

There is after all a thing/place called CERN where they are accelerating particles [VELOCITY] to discover new elements of this Universe. That's quite beyond the concept of "characterisation".