[yoo] 
| 1. | the 21st letter of the English alphabet, a vowel. |
| 2. | any spoken sound represented by the letter U or u, as in music, rule, curious, put, or jug. |
| 3. | something having the shape of a U. |
| 4. | a written or printed representation of the letter U or u. |
| 5. | a device, as a printer's type, for reproducing the letter U or u. |
[yoo] ,| characteristic of or appropriate to the upper class, esp. of Great Britain. |
[oo] ,| a Burmese title of respect applicable to a man: used before the proper name. |
| 1. | (on a packaged product) certified as kosher by the Union of Orthodox Hebrew Congregations. |
| 2. | the 21st in order or in a series, or, when I is omitted, the 20th. |
| 3. | Chemistry. uranium. |
| 4. | Biochemistry. uracil. |
| 5. | Thermodynamics. internal energy. |
| 6. | British. a designation for motion pictures determined as being acceptable for viewing by all age groups. Compare A (def. 11), X (def. 9). |
| 1. | uncle. |
| 2. | and. Origin: < G und |
| 3. | uniform. |
| 4. | union. |
| 5. | unit. |
| 6. | united. |
| 7. | university. |
| 8. | unsatisfactory. |
| 9. | upper. |
| internal energy n. Symbol U The total kinetic and potential energy associated with the motions and relative positions of the molecules of an object, excluding the kinetic or potential energy of the object as a whole. An increase in internal energy results in a rise in temperature or a change in phase. |
| u 1 or U (yōō) n. pl. u's or U's also us or Us
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| u 2 abbr. up quark |
| U 1 (yōō) adj. Chiefly British Of or appropriate to the upper class, especially in language usage. [u(pper class).] |
| U 2 (ōō) n. Used as a courtesy title before the name of a man in a Burmese-speaking area. [Burmese.] |
U 3
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| U 4 abbr.
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| up quark n. Abbr. u A quark with a charge of + 2/3 and a mass about 607 times that of the electron. It is a component of protons and neutrons. See Table at subatomic particle. |
| u·ra·cil (yŏŏr'ə-sĭl) n. Abbr. U A pyrimidine base, C4H4N2O2, that is an essential constituent of RNA. [ur(ea) + ac(etic) + -il, substance relating to.] |
| u·ra·ni·um (yŏŏ-rā'nē-əm) n. Symbol U A heavy silvery-white metallic element, radioactive and toxic, easily oxidized, and having 14 known isotopes of which U 238 is the most abundant in nature. The element occurs in several minerals, including uraninite and carnotite, from which it is extracted and processed for use in research, nuclear fuels, and nuclear weapons. Atomic number 92; atomic weight 238.03; melting point 1,132°C; boiling point 3,818°C; specific gravity 18.95; valence 2, 3, 4, 5, 6. See Table at element. [New Latin ūranium, after Ūranus, Uranus; see Uranus.] Word History: Some chemical elements, such as ytterbium and berkelium, derive their names from the places they were discovered, but the element uranium owes its name to an earlier scientific discovery, that of the planet Uranus. Sir William Herschel, who discovered Uranus in 1781, wanted to name the planet Georgium sidus, "the Georgian planet," in honor of George III; others called it Herschel. Eventually convention prevailed and the planet came to be called Uranus, like Mercury and Pluto the name of a heavenly deity in classical mythology. This god, called Ouranos in Greek (Latinized as Uranus), was chosen because he was the father of Saturn (Greek Kronos), the deity of the planet next in line, who himself was the father of Jupiter (Greek Zeus), the deity of the next planet. The name of this new planet Uranus was then used in the name of a new chemical element discovered eight years later by M.H. Klaproth. Klaproth, a German scientist, gave it the Latin name uranium in honor of the discovery of Uranus. Uranium passed into English shortly thereafter, being first recorded in the third edition of the Encyclopedia Britannica, published in 1797. |
U
A Nasdaq stock symbol specifying that the issue is in units.
Investopedia Commentary
Nasdaq-listed securities have four or five characters. If a fifth letter appears, it identifies the issue as other than a single issue of common stock or capital stock.
See also: Nasdaq, Stock Symbol
Also spelled: U
u
U 3
The symbol for the element uranium.
| u up quark |
U
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