'Diaereses' definitions:

Definition of 'Diaereses'

From: GCIDE

Diaeresis \Di*[ae]r"e*sis\, Dieresis \Di*er"e*sis\ (?; 277), n.; pl. Di[ae]reses or Diereses. [L. diaeresis, Gr. ?, fr. ? to divide; dia` through, asunder + ? to take. See Heresy.]
1. (Gram.) The separation or resolution of one syllable into two; -- the opposite of syn[ae]resis. [1913 Webster]
2. A mark consisting of two dots [[umlaut]], placed over the second of two adjacent vowels, to denote that they are to be pronounced as distinct letters; as, co["o]perate, a["e]rial. [1913 Webster]