The Collaborative International Dictionary of English v.0.48:

curium \curium\ n. [after Pierre and Marie Curie.]
   a radioactive transuranic element of atomic number 96, having
   an atomic weight of 247 for its most stable isotope
   (half-life 1.6 x 10^7 years). The chemical symbol is Cm.

   Note: It was first prepared in 1944 by helium-ion bombardment
         of plutonium in a cyclotron by Glenn Seaborg and
         colleagues in California. It has never been detected in
         nature, though minute quantities may exist in uranium
         deposits as a consequence of the neutron flux there.

   Syn: Cm, atomic number 96.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

curium
    n 1: a radioactive transuranic metallic element; produced by
         bombarding plutonium with helium nuclei [syn: curium,
         Cm, atomic number 96]