The English word with the most consecutive vowels is euouae.
Euouae is a six-letter musical mnemonic made entirely from vowels: e-u-o-u-a-e. It represents the ending of the Latin phrase “seculorum Amen,” from the Gloria Patri in Gregorian chant. Medieval scribes used it in liturgical books to remember melodic endings of psalm tones.
The word is unusual because it is both extremely short and vowel-heavy. Guinness World Records lists it as the English word with the most consecutive vowels and as the longest word consisting only of vowels. Collins English Dictionary and major Scrabble dictionaries also recognize it, although its Latin liturgical origin means some linguists question whether it should be treated as an ordinary English word.
A common mix-up is queueing, which has five consecutive vowel letters in standard spelling. Euouae has six, though it is much less familiar and is primarily encountered in word records, dictionaries, and discussions of Gregorian music. The plural form, euouaes, adds a consonant-free ending and is also accepted in some word-game dictionaries.