Merriam-Webster's Collegiate® Dictionary, 11th Edition
DEFINITIVE
I. adjective
Etymology: Middle English diffinityf, from Anglo-French diffinitive, from Latin definitivus, from definitus
Date: 14th century
serving to provide a final solution or to end a situation , authoritative and apparently exhaustive ,
3. serving to define or specify precisely , serving as a perfect example ; quintessential , fully differentiated or developed , issued as a regular stamp for the country or territory in which it is to be used, see: conclusive definitively adverb definitiveness noun
II. noun
Date: 1951
a definitive postage stamp