What is a compact model?
This paper uses the phrases "compact model" and "multiscale simulation". Perhaps it is relevant. Indeed, Googling "multiscale simulation compact model" yielded lots of results.

The back cover of the book you refer to states:


  Compact Models of circuit elements are models that are sufficiently simple to be incorporated in circuit simulators and are sufficiently accurate to make the outcome of the simulators useful to circuit designers. The conflicting objectives of model simplicity and accuracy make the compact modeling field an exciting and challenging research area for device physicists, modeling engineers and circuit designers.


My understanding is that a compact model is a parametric equation with certain parameters determined that models the phenomenon of interest to some degree of precision.