U

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

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

U was originally a positional variant of the letter V, as J was of I, used only in lower-case writing and only medially, and representing both the vowels now written with U and the consonants now written with V. The use of the two forms to distinguish consonants and vowels was not made until modern times.

Alternative representations

Uniform represents the letter U in the NATO phonetic alphabet.

In international Morse code the letter U is DitDitDah: · · -

In Braille the letter U is represented as ⠥ (in Unicode), the dot pattern:

X.
..
XX

Computing

In Unicode the capital U is codepoint U+0055 and the lowercase u is U+0075.

The ASCII code for capital U is 85 and for lowercase u is 117; or in binary 01010101 and 01110101, correspondingly. The EBCDIC code for capital U is 228 and for lowercase u is 164.

The numeric character references in HTML and XML are "U" and "u" for upper and lower case respectively.

Meanings for U

• 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, stands for union and the upside-down 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 pronunciation.

See also

• Ù
• Ú
• Û
• Ü
• Ŭ
• Ű
• Ů