This was also my understanding of 'state', I didn't know it was a libertarian definition. What other definitions are commonly used?
Discussion
That's the same definition in statistspeak (trying to legitimize state violence) and wrongly ignoring issue of physical location, which is in fact necessary.
Enforcement of the monopoly on violence always is delimited by an area where thst monopoly applies. Even if it was the entire universe you must specify that it's in the entire universe.