[d??'??r?s?s, -'?r-]
(US dieresis)
¦ noun (plural diaereses -si:z)
1. a mark (?) placed over a vowel to indicate that it is sounded separately, as in naive, Bronte.
the division of a sound into two syllables, especially by sounding a diphthong as two vowels.
2. Prosody a natural rhythmic break in a line of verse where the end of a metrical foot coincides with the end of a phrase.
Origin
C16: via L. from Gk diairesis 'separation', from diairein 'take apart'.