Euouae

Euouae (/juː.ˈuː.iː/ yew-OO-ee; sometimes spelled Evovae)[1] is an abbreviation used as a musical mnemonic in Latin psalters and other liturgical books of the Roman Rite.

The mnemonic is used to notate the variable melodic endings (differentiae) of psalm tones in Gregorian chant.

According to Guinness World Records, Euouae is the longest word in the English language consisting only of vowels, and also the English word with the most consecutive vowels.

[4] Its all-vowel composition makes it an effective play for certain kinds of vowel-heavy Scrabble racks, and the plural form ("euouaes") means a bingo can be made in certain situations.

In Venetian and other Italian Office books of the 16th century, an equivalent abbreviation, Hal'a, or Hal'ah, can be substituted for Aevia.