diacritic

A diacritic (/daɪəˈkrɪtɪk/) (also diacritical mark, diacritical point, diacritical sign) is an ancillary glyph added to a letter, or basic glyph. The term derives from the Greek διακριτικός (diakritikós, "distinguishing"). Diacritic is both an adjective and a noun, whereas diacritical is only an adjective. Some diacritical marks, such as the grave and acute, but not the cedilla, are often called accents. Diacritical marks may appear above or below a letter, or in some other position such as within the letter.