Hi
the term typically applies to a person who acquires/buys/registers a domain and develops it into a viable website.
however, every domainer is the enduser for each name they own... at least until they sell the name or they drop it.
as you become the last user of the name.
still, in today's times,
there are way more "endusers" or deep pocket mofo's participating in drop catching, backordering and other domain auction activities than in the past.
it's one reason why you might see some outrageous bids for some names, as well as closing prices in general being much higher than before.
but that's the fault of domainer community for always wanting to tell outsiders wtf they're doing.
imo...