diacritic: a small mark used together with a letter, indicating either a variation on the same sound (such as stress or a particular tone) or a different, though often similar, sound. Common diacritics include the acute accent ( ˊ ), grave accent ( ˋ ), macron ( ˉ ), circumflex (caret, ˆ ), wedge (hachek, caron, ˇ ), tilde ( ˜ ) and dieresis (umlaut, ¨ ). [Spanish: diacrítico]