diacritic /ˌdaɪəˈkɹɪtɪk/adjective 2noun 2forms 3 adjective2 •Distinguishing. •Denoting a distinguishing mark applied to a letter or character. noun2 •A special mark added to a letter to indicate a different pronunciation, stress, tone, or meaning. •A letter added to another letter serving a similar indicative function.A notable feature in N is the frequent oa spellings […] The a is here a diacritic which is meant to distinguish /ɔ̄/ from /ō/ on the model of the distinction ea /ǣ/—e /ē/ in the AB texts. — 1965 formsdiacritics · more diacritic · most diacritic