Definition of "diacritical" [diacritical]

• Marking a distinction; distinguishing. (adjective)
• Able to discriminate or distinguish: a mind of great diacritical power. (adjective)
• Serving as a diacritic. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "First of all, I apologize that I do not know how to make my computer put the diacritical markings on the Spanish words."
• "Errors and omissions in Greek diacritical marks have been silently corrected."
• "In the pronunciation guide you will see some strange characters called diacritical marks above or below a letter to modify the way a word is pronounced."