definitive

[ dih-fin-i-tiv ]
/ dɪˈfɪn ɪ tɪv /

adjective

most reliable or complete, as of a text, author, criticism, study, or the like: the definitive biography of Andrew Jackson.
serving to define, fix, or specify definitely: to clarify with a definitive statement.
having its fixed and final form; providing a solution or final answer; satisfying all criteria: the definitive treatment for an infection; a definitive answer to a dilemma.
Biology. fully developed or formed; complete.

noun

a defining or limiting word, as an article, a demonstrative, or the like.
Philately. a stamp that is a regular issue and is usually on sale for an extended period of time.Compare commemorative(def 2).

Origin of definitive

1350–1400; Middle English < Old French < Latin dēfīnītīvus, equivalent to dēfīnīt(us) (see definite) + -īvus -ive
Related forms
Can be confuseddefinite definitive
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for definitive

British Dictionary definitions for definitive

definitive

/ (dɪˈfɪnɪtɪv) /

adjective

serving to decide or settle finally; conclusive
most reliable, complete, or authoritativethe definitive reading of a text
serving to define or outline
zoology fully developed; completethe definitive form of a parasite
  1. (of postage stamps) permanently on sale
  2. (as noun) a definitive postage stamp

noun

grammar a word indicating specificity of reference, such as the definite article or a demonstrative adjective or pronoun
Derived Formsdefinitively, adverbdefinitiveness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012