or di·aer·e·sis

noun, plural di·er·e·ses [dahy-er-uh-seez] /daɪˈɛr əˌsiz/.
  1. the separation of two adjacent vowels, dividing one syllable into two.
  2. a sign (¨) placed over the second of two adjacent vowels to indicate separate pronunciation, as in one spelling of the older forms naïve and coöperate: no longer widely used in English.
  3. Prosody. the division made in a line or verse by coincidence of the end of a foot and the end of a word.

Origin of dieresis

1605–15; < Latin diaeresis < Greek diaíresis literally, distinction, division, equivalent to diaire-, stem of diaireîn to divide (di- di-3 + haireîn to take) + -sis -sis
Related formsdi·e·ret·ic [dahy-uh-ret-ik] /ˌdaɪ əˈrɛt ɪk/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for dieretic


noun plural -ses (-ˌsiːz)
  1. a variant spelling of diaeresis
Derived Formsdieretic (ˌdaɪəˈrɛtɪk), adjective
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 dieretic



also diaeresis, 1610s, "sign marking the division of a diphthong into two simple sounds," from Late Latin diaeresis, from Greek diairesis "division," noun of action from diairein "to divide, separate," from dia- "apart" (see dia-) + hairein "to take" (see heresy).

Online Etymology Dictionary, © 2010 Douglas Harper

dieretic in Medicine


  1. Of or relating to dieresis.
  2. Dividing; ulcerating; corroding.


  1. solution of continuity
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.