Vowel hiatus
OCCURRENCE OF TWO VOWEL SOUNDS IN ADJACENT SYLLABLES, WITH NO INTERVENING CONSONANT
Diaeresis (linguistics); Vowel sequence; Hiatus (linguistics)
In phonology, hiatus, diaeresis (), or dieresis describes the occurrence of two separate vowel sounds in adjacent syllables with no intervening consonant. When two vowel sounds instead occur together as part of a single syllable, the result is called a diphthong.