"Definitive" means that whatever your talking about is the
last word on its
subject matter. Its usual
context is "the definitive work", which means a
book or
publication that is
forever after the
reference and
source material for any other publications or
research on that subject. To write the definitive work on a subject, you either need to be an incredible
expert or to be the
first to study it, but ideally both.
Everything2 is the definitive reference for everything Or it will be, someday.