difference between "Graded, Scaled, Progressive, Weighted" hammer action?

[garywang]

Hi there, are the "graded hammer", "scaled hammer", "progressive hammer", "weighted hammer" the same thing?

Yamaha, Casio, Roland, Korg use their own adverts language:
https://www.musiciansbuy.com/digital-piano-Comparison.asp

What are the differences between them if they are different?

Also, some models say "3-level" action, what is this about? keys respond with 3-level jumping sensitivities, instead of a continuous linear sensitivity?

Thanks.