From the wiki
Definition:
Connected to a terminal or easily walkable (~300m) from the terminal on a safe pathway in a short time by the average person (with luggage) without the need for a shuttle.
Includes use of dedicated free on-airport moving walkways/train/tram/bus for larger multi terminal airports.
Unfortunately the wiki entries now contains some reference to hotels ~ light rail - metro stops down the line. Those cannot be considered
"Hotels on Airport Premises" as per thread title.