Definitions

from The American Heritage® Dictionary of the English Language, 4th Edition

  • adv. For a still stronger reason; all the more.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. With stronger or greater reason; as a corollary implied by a stronger claim.
  • adv. With stronger or greater reason; as a corollary implied by a stronger claim.

from the GNU version of the Collaborative International Dictionary of English

  • With stronger reason.

from The Century Dictionary and Cyclopedia

  • For a still stronger reason; all the more.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adv. with greater reason; for a still stronger, more certain reason

Etymologies

Latin : ā, ab, from + fortiōrī, ablative of fortior, stronger.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin ā ("from") and fortiōrī, comparative of fortis ("strength"). (Wiktionary)

Examples

  • On the contrary it helps to emphasize this truth, for the same relation of dependence upon a self-existing cause which is implied in the contingency of any single being is implied a fortiori in the existence of an infinite series of such beings, supposing such a series to be possible.

    The Catholic Encyclopedia, Volume 6: Fathers of the Church-Gregory XI

  • The Biblical Commission (15 Feb., 1909) has decreed the historicity of the primitive narrative of Gen., i-iii; a fortiori it will not tolerate that a Catholic deny the historicity of Josue.

    The Catholic Encyclopedia, Volume 8: Infamy-Lapparent

  • Since the impressions of sense leave lasting traces on the bodily which is subject to decay, — a fortiori the universal must, in some way, be stored up in the passive intellect, which is a spiritual faculty, permanent as the soul itself (I, Q., lxxix, a, 6-7).

    The Catholic Encyclopedia, Volume 10: Mass Music-Newman

Comments

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  • JM for no reason at all reckons a fortiori

    November 12, 2010

  • A mediaeval alteration of Classical a fortiore.

    June 3, 2009

  • An A fortiori argument is one that "denotes a proof of a claim by means of an already proved stronger claim."

    February 28, 2009