Uranium

noun, Chemistry.
1.
a white, lustrous, radioactive, metallic element, occurring in pitchblende, and having compounds that are used in photography and in coloring glass. The 235 isotope is used in atomic and hydrogen bombs and as a fuel in nuclear reactors. Symbol: U; atomic weight: 238.03; atomic number: 92; specific gravity: 19.07.
noun
1.
a radioactive silvery-white metallic element of the actinide series. It occurs in several minerals including pitchblende, carnotite, and autunite and is used chiefly as a source of nuclear energy by fission of the radioisotope uranium-235. Symbol: U; atomic no: 92; atomic wt: 238.0289; half-life of most stable isotope, 238U: 451 × 109 years; valency: 2-6; relative density: 18.95 (approx.); melting pt: 1135°C; boiling pt: 4134°C

uranium u·ra·ni·um (yu-rā’nē-əm)
n.
Symbol U
An easily oxidized radioactive toxic metallic element having 16 known isotopes, of which U 238 is the most naturally abundant. Atomic number 92; atomic weight 238.03; melting point 1,135°C; boiling point 4,151°C; specific gravity 18.95; valence 2, 3, 4, 5, 6.
uranium
(y-rā’nē-əm)
Symbol U
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.

uranium definition

A chemical element that is naturally radioactive. An isotope of uranium, uranium 235, is the main fuel for nuclear reactors and atomic bombs. Its symbol is U. (See fission and chain reaction.)