Y

Y, or Ÿ, is the twenty-fifth (number 25) letter in the English alphabet.^[1] Its name in English is "wye" (pronounced /ˈwaɪ/).^[2]

The Latin alphabet
	Aa	Bb	Cc	Dd
Ee	Ff	Gg	Hh	Ii	Jj
Kk	Ll	Mm	Nn	Oo	Pp
Qq	Rr	Ss	Tt	Uu	Vv
	Ww	Xx	Yy	Zz

In words like year, yell, and yes, the Y is a consonant (semivowel). In words like cry, fly, and sky, the Y is considered a vowel.

Where it came from

Semitic, Phoenician, Greek and Latin

• 
  An early Semitic version of the letter waw
• 
  The later Phoenician version of waw

"Y" has appeared as the Semitic letter "waw". This was the first time it appeared in an alphabet. F, U, V, and W also come from the Semitic alphabet. The Greek and Latin alphabets used the Phoenician form of this early alphabet. There are similarities to the old English letter yogh (Ȝȝ). The table shows where the letter "y" came from.

Where the English letter "Y" came from

Phoenician	Greek	Latin	English (approximate times of changes)
			Old	Middle	Now
		→	U →	/U/UU →	/U/
		→	(vowel /y/) →	(vowel /i/) →	(vowels)
		C →
		G →	Ȝ →	G →
				consonantal /j/ →	(consonant)
			Þ →	/th/	-

Meanings for Y

• In chemistry, Y is the symbol for yttrium.
• In mathematics, y is another unknown variable, used as a second unknown variable ("x" is used as the first unknown variable)

References

1. "Y" Oxford English Dictionary, 2nd edition (1989); Merriam-Webster's Third New International Dictionary of the English Language, Unabridged (1993); "wye", op. cit.
2. "Y", Oxford English Dictionary, 2nd edition (1989); Merriam-Webster's Third New International Dictionary of the English Language, Unabridged (1993); "wye", op. cit.