The big difference between what Frost describes as a pattern or pattern library and the meaning from Alexander (who created the concept) is the idea that 'all design exists to solve a problem', and that a Pattern must state the problem that it is the generalized solution to. That part has gotten lost in most of the interpretations of his work from OOP patterns in CompSci, to these UI patterns. I highly recommend checking out the source material, the book "A Pattern Language" is a great place to start.