From what I have managed to google of it the working set refers to how much ram it's using and the pagefile refers to how much it has reserved, unfortunately that's the most I could infer from what I could get a hold of, the sites, threads & comments never seem to explain beyond the working set and saying that it equates to the residential memory in linux etc.
All I'd like to know is what is the non-jargon or at least reduced jargon explaination for ALL the parameters (except cb, I don't understand why M$ felt the need to add that twice, on the struct and the function that fills it)

Edit: The best I could come up with to understand it myself is this:
typedef struct memcount {
	size_t size;
	size_t peak;
} memcount_t;
typedef struct memusage {
	size_t theory; /* Fantasy limit of memory */
	size_t faults; /* Page Faults */
	memcount_t physical; /* RSS / Working */
	memcount_t reserved; /* VSZ / Pagefile */
	memcount_t nowusing; /* Paged */
	memcount_t hovering; /* Not Paged */
} memusage_t;