The Collaborative International Dictionary of English v.0.48:

Samarium \Sa*ma"ri*um\, n. [NL., fr. E. samarskite.] (Chem.)
   A rare metallic element of doubtful identity.
   [1913 Webster]

   Note: Samarium was discovered, by means of spectrum analysis,
         in certain minerals (samarskite, cerite, etc.), in
         which it is associated with other elements of the
         earthy group. It has been confounded with the doubtful
         elements decipium, philippium, etc., and is possibly a
         complex mixture of elements not as yet clearly
         identified. Symbol Sm. Provisional atomic weight 150.2.
         [1913 Webster]

WordNet (r) 3.0 (2006):

samarium
    n 1: a grey lustrous metallic element of the rare earth group;
         is used in special alloys; occurs in monazite and
         bastnasite [syn: samarium, Sm, atomic number 62]

The Elements (07Nov00):

samarium
Symbol: Sm
Atomic number: 62
Atomic weight: 150.35
Soft silvery metallic element, belongs to the lanthanoids. Seven natural
isotopes, Sm-147 is the only radioisotope, and has a half-life of
2.5*10^11 years. Used for making special alloys needed in the production
of nuclear reactors. Also used as a neutron absorber. Small quantities
of
samarium oxide is used in special optical glasses. The largest use of
the
element is its ferromagnetic alloy which produces permanent magnets that
are five times stronger than magnets produced by any other material.
Discovered by Francois Lecoq de Boisbaudran in 1879.