A diacritic (also diacritical mark, diacritical point, diacritical sign, or accent) is a glyph added to a letter or to a basic glyph. The term derives from the Ancient Greek διακριτικός (diakritikós, "distinguishing"), from διακρίνω (diakrī́nō, "to distinguish"). The word diacritic is a noun, though it is sometimes used in an attributive sense, whereas diacritical is only an adjective. Some diacritics, such as the acute ( ´ ) and grave ( ` ), are often called accents. Diacritics may appear above or below a letter or in some other position such as within the letter or between two letters.