[ahy-den-ti-kuhl, ih-den-]
  1. similar or alike in every way: The two cars are identical except for their license plates.
  2. being the very same; selfsame: This is the identical room we stayed in last year.
  3. agreeing exactly: identical opinions.

Origin of identical

1610–20; < Medieval Latin identic(us) identic + -al1
Related formsi·den·ti·cal·ly, adverbi·den·ti·cal·ness, nounnon·i·den·ti·cal, adjectivepseu·do·i·den·ti·cal, adjectivequa·si-i·den·ti·cal, adjectivequa·si-i·den·ti·cal·ly, adverbun·i·den·ti·cal, adjectiveun·i·den·ti·cal·ly, adverb

Synonyms for identical

3. congruous, congruent, equal, matching. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for nonidentical


  1. Also called: numerically identical being one and the same individualCicero and Tully are identical
  2. Also called: quantitatively identical exactly alike, equal, or agreeing
  3. designating either or both of a pair of twins of the same sex who developed from a single fertilized ovum that split into twoCompare fraternal (def. 3)
Derived Formsidentically, adverbidenticalness, noun

Word Origin for identical

C17: from Medieval Latin identicus, from Latin idem the same
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

Word Origin and History for nonidentical



1610s, as a term in logic, from Medieval Latin identicus "the same," from Late Latin identitas "identity, sameness," ultimately from comb. form of Latin idem "the same" (from id "it, that one;" see id) + demonstrative suffix -dem. General sense of "being the same or very similar" is from 1630s. Replaced Middle English idemptical (late 15c.), from Medieval Latin idemptitas "identity," from Latin idem. Related: Identically.

Online Etymology Dictionary, © 2010 Douglas Harper

nonidentical in Medicine


  1. Not being the same; different.
  2. Fraternal, as of twins.


  1. Exactly equal and alike.
  2. Of or relating to a twin or twins developed from the same fertilized ovum and having the same genetic makeup and closely similar appearance; monozygotic.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.