U

U is the twenty-first letter of the modern Latin alphabet.

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U was originally a capital letter like J and it was only Pierre de la Ram?e who made the distinction between capital and small letter. See V.

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Uniform represents the letter U in the NATO phonetic alphabet.

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• In biochemistry, U is the symbol for uracil.
• In calendars, U is often an abbreviation for Sunday, for use when S is being used for Saturday.
• In chemistry, U is the symbol for uranium.
• In communication, u is an abbreviation for the word "you" in SMS or instant message.
• In computing, 1 U (= 44 mm or 1.75 inch) is a standard unit of height of a piece of equipment or computer chassis in a 19-inch rack, also called a rack unit (RU) or a pizza box.
• In education, U is an unsatisfactory grade.
• In electrical engineering, U is the symbol for voltage.
• In history, U is king of Goryeo(Korea).
• In linguistics, U refers to speech markers of upper class British speakers. British novelist Nancy Mitford brought to popular attention the linguistic terminology "U" and "non-U" to indicate the speech markers of upper class and non-upper class British speakers respectively.
• U also stands for the popular Shia name Umar as Umar is seen as too sacred to be said aloud
• In mathematics, $cup$ stands for union and the upside-down $cap$ stands for intersection (both are operators on sets). A U-set is a set of uniqueness.
• In mathematics, U stands for the unitary group.
• In metrology, u is the symbol for unified atomic mass unit.
• In military science, U- is a prefix used for German submarines during World War II, (e.g., U-20), which was short for Unterseeboot. They were also referred to as "U-boats" by the Allies.
• In the Unicode standard, character code points are labelled "U+" followed by a number in hexadecimal.
• University of Miami, owing to its distinctive split-U logo
• University of Utah or "U of U" (or just University in general).
• In Internet slang, "u" or "U" is referred to as "you" due to the similarity in pronounciation

J: For the programming language, see J programming language....

V: :This article is about the alphabetic letter. For the TV series, see V (TV series)....