Definition of U:

• ( chiefly British) of or appropriate to the upper classes especially in language use
• 1. The chemical symbol of uranium. 2. Abbreviation for unit. 3. Symbol for kilurane, or 1000 uranium units.
• Twenty- first letter of the alphabet.
• Is the fifth vowel and the twenty- first letter of the English Alphabet. It has four distinct vocal sounds; the first is short and acute, as in hut; the second a little longer, as in truth; the third long and close, as in mute; and the fourth short and obscure, as in fur, ful, & c. In many words it takes the sound of yu, as in unison; and sometimes of 00, as rule.
• the twenty-first letter of the English alphabet, is a cursive form of the letter V, with which it was formerly used interchangeably, both letters being then used both as vowels and consonants. U and V are now, however, differentiated, U being used only as a vowel or semivowel, and V only as a consonant. The true primary vowel sound of U, in Anglo-Saxon, was the sound which it still retains in most of the languages of Europe, that of long oo, as in tool, and short oo, as in wood, answering to the French ou in tour. Etymologically U is most closely related to o, y vowel, w, and v; as in two, duet, dyad, twice; top, tuft; sop, sup; auspice, aviary. See V, also O and Y.
• a heavy toxic silvery- white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons
• The twenty- first letter in the English alphabet.

Usage examples for U

1. But I was born in the U. S. And if it suits me I will be for America.  The Desert of Wheat by Zane Grey

2. The U. P. R. is going through.  The U.P. Trail by Zane Grey

3. These U. E. rights were bought at the rate of 1s.  Roughing it in the Bush by Susanna Moodie

4. Oh, you can make me out an I O U some time, and get Jimmy to witness it, if you're so damned- what's the word?  Foe-Farrell by Arthur Thomas Quiller-Couch