Y is the twenty-fifth letter in the ISO basic Latin alphabet. The letter Y can be regarded as both a vowel and a consonant
In terms of sound, a vowel is ‘a speech sound which is produced by comparatively open configuration of the vocal tract, with vibration of the vocal cords but without audible friction, while a consonant is a basic speech sound in which the breath is at least partly obstructed. The consonant sound is not consistently represented in English spelling by any other letter, and perhaps for this reason Y tends traditionally to be counted among the consonants. The usage of the capital form of upsilon, Y as opposed to U, V, or W, dates back to the Latin of the first century BC, when upsilon was introduced a second time, this time with its foot to distinguish it
  • Y in metrology symbol for prefix yotta
  • Y in genetics 1-letter abbreviation for any pyrimidine
  • Y in yep new hebrides islands expression for sexual intercourse
  • Y in yak variant of yuck: to laugh Y is an abstract strategy board game
  • Y in sound department stands for Y – cable

wikipedia, Encyclopædia Britannica, www.cavitas-oris.com