Learn how to say Diacritic correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word diacritic:
a sign, such as an accent or cedilla, which when written above or below a letter indicates a difference in pronunciation from the same letter when unmarked or differently marked.
(of a mark or sign) indicating a difference in pronunciation.
late 17th century: from Greek diakritikos, from diakrinein ‘distinguish’, from dia- ‘through’ + krinein ‘to separate’