Y is the twenty-fifth letter of the Latin alphabet.
See V. In Greek Υψιλον (Ypsilon) was pronounced /u/ (later on /y/, now /i/; see English MYTH and GIFT which both have /I/). The Romans borrowed Y directly from the Greek, because they felt that V no longer adequately represented Greek /y/. The English name of the letter - /waI/ - is of unknown origin. In Spanish, Y is called i griega, in Catalan i grega and in French i grec (all mean "Greek i"); in most other European languages the Greek name is still used. The letter Y was originally established as a vowel. It is now established both as a vowel and as a consonant. On Wheel of Fortune, the letter Y counts as a consonant.
The letter y was used by Caxton and other printers in mediaeval England to represent the thorn.
Yankee represents the letter Y in the NATO phonetic alphabet.
Y is also: