U is a letter of the English alphabet. U is also a letter of the Cyrillic alphabet corresponding to the Greek letter Upsilon, with a numeric value of 400. U in Greek is Y (Yu) or u as in Upsilon and is said to derive from Phoenican Waw. http://en.wikipedia.org/wiki/Upsilon In India, U is the middle vowel of AUM and represents Vishnu. Creator Preserver Destroyer A U M Brahma Vishnu Shiva