a radioactive, metallic chemical element, one of the actinides, produced by the nuclear bombardment of curium: symbol, No; at. no., 102
See nobelium in American Heritage Dictionary 4
(nō-bĕlˈē-əm)
noun Symbol No
A radioactive transuranic element in the actinide series with atomic number 102, artificially produced in trace amounts. Its most long-lived isotopes are No 254 with a half-life of 55 seconds, No 253 with a half-life of 1.7 minutes, No 255 with a half-life of 3.1 minutes, and No 259 with a half-life of 58 minutes. See Table at element.