syn·i·ze·sis 
(sĭn′ĭ-zēsĭs)
(sĭn′ĭ-zēsĭs)n. pl. syn·i·ze·ses (-sēz)
1. Linguistics The union in pronunciation of two adjacent vowels into one syllable without forming a diphthong.
2. Biology The phase of meiosis in some species in which the chromatin contracts into a mass at one side of the nucleus.
[Late Latin synizēsis, from Greek sunizēsis, from sunizein, to collapse : sun-, syn- + hizein, to settle down; see sed- in the Appendix of Indo-European roots.]