U
1 Americannoun
plural
U's, Us, u's, us-
the 21st letter of the English alphabet, a vowel.
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any spoken sound represented by the letter U or u, as in music, rule, curious, put, or jug.
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something having the shape of a U .
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a written or printed representation of the letter U or u.
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a device, as a printer's type, for reproducing the letter U or u.
pronoun
adjective
noun
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(on a packaged product) certified as kosher by the Union of Orthodox Hebrew Congregations.
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the 21st in order or in a series.
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Chemistry. uranium.
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Biochemistry. uracil.
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Thermodynamics. internal energy.
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British. a designation for motion pictures determined as being acceptable for viewing by all age groups.
abbreviation
abbreviation
-
uniform.
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unit.
-
unsatisfactory.
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upper.
abbreviation
abbreviation
-
uncle.
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uniform.
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union.
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unit.
-
united.
-
university.
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unsatisfactory.
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upper.
symbol
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united
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unionist
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university
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-
universal (used to describe a category of film certified as suitable for viewing by anyone)
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( as modifier )
a U film
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-
chem uranium
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biochem uracil
abbreviation
adjective
abbreviation
-
maths union
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unit
-
united
-
university
-
upper
noun
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the 21st letter and fifth vowel of the modern English alphabet
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any of several speech sounds represented by this letter, in English as in mute, cut, hurt, sure, pull, or minus
-
-
something shaped like a U
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( in combination )
a U-bolt
a U-turn
-
noun
Etymology
Origin of U2
First recorded in 1840–45
Origin of U3
First recorded in 1950–55; u(pper class)
Origin of U4
First recorded in 1930–35; from Burmese ʔú, roughly “Mister, Uncle,” used for senior men and monks
Origin of u.6
From the German word und
Origin of U.8
From the German word und
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Only 10,000 U visas become available each year, and many more applicants qualify.
From The Wall Street Journal • Apr. 22, 2026
Earlier this month, a federal grand jury in Boston indicted 10 Indian nationals for allegedly staging convenience-store holdups in Massachusetts and elsewhere to secure U visas.
From The Wall Street Journal • Apr. 21, 2026
"Even though the material itself isn't magnetic, the existence of chiral phonons gives us these magnetic levers to pull on," said Rikard Bodin, doctoral candidate at the U and co-author of the paper.
From Science Daily • Apr. 19, 2026
"We saw a few U turns in the wake of Trump's original announcement last night," says Richard Meade, editor-in-chief of Lloyd's list.
From BBC • Apr. 13, 2026
A wave of relief surges through me as we start down the hall to the bottom of the U, away from the danger.
From "Amari and the Night Brothers" by B.B. Alston
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.