|u or U (juː)|
|—n , pl u's, U's, Us|
|1.||the 21st letter and fifth vowel of the modern English alphabet|
|2.||any of several speech sounds represented by this letter, in English as in mute, cut, hurt, sure, pull, or minus|
|3.||a. something shaped like a U|
|b. (in combination): a U-bolt; a U-turn|
|U or U|
|a. universal (used to describe a category of film certified as suitable for viewing by anyone)|
|b. (as modifier): a U film|
|7.||text messaging you|
|8.||old-fashioned, informal (Brit) Compare non-U (esp of language habits) characteristic of or appropriate to the upper class|
The symbol for the element uranium.
|uranium (y-rā'nē-əm) Pronunciation Key
A heavy, silvery-white, highly toxic, radioactive metallic element of the actinide series. It has 14 known isotopes, of which U 238 is the most naturally abundant, occurring in several minerals. Fissionable isotopes, especially U 235, are used in nuclear reactors 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 Periodic Table.