Synizesis

noun

1. The union in pronunciation of two adjacent vowels into one syllable without forming a diphthong.
2. The phase of meiosis in some species in which the chromatin contracts into a mass at one side of the nucleus.
3. In medicine, closure of the pupil; an obliteration of the pupil of the eye, causing a total loss of vision.
4. In grammar, the combination into one syllable of two vowels that would not form a diphthong.
5. An obliteration of the pupil of the eye.