from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. The 21st letter of the modern English alphabet.
  • n. Any of the speech sounds represented by the letter u.
  • n. The 21st in a series.
  • n. Something shaped like the letter U.
  • n. A grade that indicates an unsatisfactory status.
  • abbr. up quark

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The twenty-first letter of the basic modern Latin alphabet.
  • n. symbol for unified atomic mass unit
  • n. Used in the International Phonetic Alphabet and in several romanization systems of non-Latin scripts to represent a close back rounded vowel (IPA: /u/).
  • n. The twenty-first letter of the English alphabet, called u and written in the Latin script.
  • n. The name of the Latin script letter U/u.
  • n. A thing in the shape of the letter U
  • pro. you (in text messaging and internet conversations)
  • abbr. Underwater.

from the GNU version of the Collaborative International Dictionary of English

  • 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.

from The Century Dictionary and Cyclopedia

  • An abbreviation [l. c] in a ship's log-book, of ugly threatening weather; [l. c] of uncle; of Unionist.
  • An abbreviation of underproof, as applied to alcoholic liquors.
  • The twenty-first character and fifth vowel-sign in the English alphabet.
  • As a symbol: The chemical symbol of uranium.
  • In quaternions, an operational sign which, prefixed to the symbol of a quaternion, denotes the versor of that quaternion.
  • In the theory of heat, a symbol used to denote the energy, or the sum of the increment of heat and the heat consumed.
  • [lowercase] In the calculus, the symbol of a function.
  • [lowercase] In hydrodynamics, used with v and w to denote the rectangular components of the velocity.
  • n. An abbreviation of United Brethren; of United Brethren in Christ.
  • n. An abbreviation of University College; of Upper Canada; of the Latin urbis conditæ, from the founding of the city, moaning from the first year of Rome.
  • n. An abbreviation of Uncle Sam
  • n. of United Service
  • n. [lowercase or cap.] of the Latin ut supra, as above.
  • n. An abbreviation of Italian una corda, on one string.
  • n. An abbreviation of United Kingdom (of Great Britain and Ireland).
  • n. An abbreviation of United Presbyterian.
  • n. An abbreviation of United States (of America).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. (chiefly British) of or appropriate to the upper classes especially in language use
  • n. a base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine
  • n. a heavy toxic silvery-white radioactive metallic element; occurs in many isotopes; used for nuclear fuels and nuclear weapons
  • n. the 21st letter of the Roman alphabet


from Wiktionary, Creative Commons Attribution/Share-Alike License

Minuscule variation of U, a modern variation of classical Latin V, from seventh century Old Latin adoption of Old Italic letter 𐌖 (V).



Log in or sign up to get involved in the conversation. It's quick and easy.

  • short for you.

    April 27, 2009

  • "U" is used as a substitute for "you" in text messages and internet chat. It will be interesting to see if it moves into everyday writing. "If U can read this, thank ur your teacher."

    April 14, 2009

  • U. Chemical element symbol for Uranium.

    December 1, 2007