Pronunciation: (u-thôr'i-tā"tiv, u-thor'-), [key]
1. having due authority; having the sanction or weight of authority: an authoritative opinion.
2. substantiated or supported by documentary evidence and accepted by most authorities in a field: an authoritative edition of Shakespeare; an authoritative treatment of a subject.
3. having an air of authority; accustomed to exercising authority; positive; peremptory; dictatorial: said with an authoritative air.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.