2. Medicine Diagnostic or distinctive.
A mark, such as the cedilla of façade or the acute accents of résumé, added to a letter to indicate a special phonetic value or distinguish words that are otherwise graphically identical.
[Greek diakritikos, distinguishing, from diakritos, distinguished, from diakrīnein, to distinguish : dia-, apart; see DIA- + krīnein, to separate; see krei- in the Appendix of Indo-European roots.]
(click for a larger image)diacritic
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.