Emily Dickinson Lexicon

DI-AL'Y-SIS, n. [Gr. διαλυσις; διαλυω, to dissolve; δια, and λυω, to dissolve.]

1. A mark in writing or printing, consisting of two points placed over one of two vowels, to dissolve a diphthong, or to show that the two vowels are to be separated in pronunciation; as, aër, mosaïc.
2. In medicine, debility; also, a solution of continuity. – Parr.