Euouae or Evovae is a mnemonic which was used in medieval music to denote the sequence of tones in the "seculorum Amen" passage of the lesser doxology, Gloria Patri, which ends with the phrase In saecula saeculorum, Amen. In plainchant sources, the differentia, that is, the melodic formula to be sung at the end of every line of chanted psalmody, would be written over either the letters EUOUAE, or merely E----E, representing the first and last vowel of "seculorum Amen."
According to the Guinness Book of World Records, at six letters long, is the longest word in the English language which is made up of nothing but vowels; it is also the English word with the most consecutive vowels.
- Apel, Willi: Gregorian Chant. Bloomington: Indiana University Press, 1990. ISBN 0-253-20601-4.
- Dyer, Joseph: «Roman Catholic Church Music» en Grove Music Online ed. L. Macy.
- Hiley, David: «Chant» in Performance Practice: Music before 1600, eds. Howard Mayer Brown & Stanley Sadie. New York: W. W. Norton, 1990, pp. 37–54. ISBN 0-393-02807-0
- Hiley, David: Western Plainchant: A Handbook. Oxford: Clarendon Press, 1995. ISBN 0-19-816572-2.
- Levy, Kenneth: «Plainchant» in Grove Music Online ed. L. Macy.