Merriam-Webster Collegiate Dictionary - identical

 adjective  Etymology: probably from Medieval Latin identicus, from Late Latin identitas  Date: 1581  1. being the same ; selfsame the ~ place we stopped before  2. having such close resemblance as to be essentially the same ~ hats — often used with to or with  3.  a. having the same cause or origin ~ infections  b. monozygotic  Synonyms: see same  • ~ly adverb  • ~ness noun