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
-
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.
Prosecutors say hundreds of people got U visas through this alleged scheme.
From The Wall Street Journal • Apr. 22, 2026
The operation netted the officers $5,000 per “victim” and helped hundreds of foreign nationals secure U visas—a status that allows certain crime victims to remain in the U.S.,
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
At lunch, we’d agreed to go on the U of Is website that week to look at the courses and application process.
From "Geeks: How Two Lost Boys Rode the Internet Out of Idaho" by Jon Katz
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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.