definitive

 
Pronunciation: /dɪˈfɪnɪtɪv/

adjective

  • 1(of a conclusion or agreement) done or reached decisively and with authority: a definitive decision
  • (of a book or other text) the most authoritative of its kind: the definitive biography of Prince Charles
  • 2(of a postage stamp) for general use and typically of standard design, not special or commemorative.

noun

  • a definitive postage stamp: low-value British definitives simply have a portrait of the reigning monarch

Derivatives

definitively

adverb

Origin:

late Middle English: from Old French definitif, -ive, from Latin definitivus, from definit- 'set within limits', from the verb definire (see define)

Definitive is often used, rather imprecisely, when definite is actually intended, to mean simply ‘clearly decided’. Although definitive and definite have a clear overlap in meaning, definitive has the additional sense of ‘having an authoritative basis’. Thus, a definitive decision is one which is not only conclusive but also carries the stamp of authority or is a benchmark for the future, while a definite decision is simply one which has been made clearly and is without doubt.