{ Di‐ær″e‐sis, Di‐er″e‐sis } (?; 277), n.; pl.DiæresesorDiereses (#). [L. diaeresis, Gr. �, fr. � to divide; διά through, asunder + � to take. See Heresy.] 1. (Gram.) The separation or resolution of one syllable into two; — the opposite of synæresis.
2. A mark consisting of two dots, placed over the second of two adjacent vowels, to denote that they are to be pronounced as distinct letters; as, coöperate, aërial.