n. [ Gr. &unr_; with one sound; mo`nos alone + &unr_; sound, voice. ] 1. A single uncompounded vowel sound. [ 1913 Webster ]

2. A combination of two written vowels pronounced as one; a digraph. [ 1913 Webster ]

a. Consisting of, or pertaining to, a monophthong. [ 1913 Webster ]