diacritical

adj. serving as a diacritical mark; distinguishing, distinctive

A diacritical mark or diacritic, also called an accent, is a small sign added to a letter to alter pronunciation or to distinguish between similar words. The term derives from Greek διακριτικός (diakritikos, "distinguishing"). "Diacritic" is both adjective and noun, whereas "diacritical" is only an adjective.
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(a.)
That separates or distinguishes; -- applied to points or marks used to distinguish letters of similar form, or different sounds of the same letter, as, a, /, a, /, /, etc.
  

Adjective
1. capable of distinguishing; "students having superior diacritic powers"; "the diacritic elements in culture"- S.F.Nadel
(synonym) diacritic
(similar) discriminating