[fulafel]

> A processor architecture is defined by its execution model (not it's external encoding).

Not quite... how these terms are actually used in computer engineering and computer architecture:

"microarchitecture": How the implementation of a given architecture looks like under the hood.

"instruction set architecture", the externally visible characteristics of the processor from software POV.

"Architecture" and "CPU architecture" usually mean ISA.

"Processor architecture" is not a widely used term, but the first several hits on google refer to the "instruction set architecture" meaning.