The Collaborative International Dictionary of English v.0.48:

Scandium \Scan"di*um\, n. [NL. So called because found in
   Scandinavian minerals.] (Chem.)
   A rare metallic element of the boron group, whose existence
   was predicted under the provisional name ekaboron by means
   of the periodic law, and subsequently discovered by spectrum
   analysis in certain rare Scandinavian minerals (euxenite and
   gadolinite). It has not yet been isolated. Symbol Sc. Atomic
   weight 44.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ekabor \Ek"a*bor`\ ([e^]k"[.a]*b[=o]r`), Ekaboron \Ek"a*bo"ron\
   (-b[=o]"r[o^]n), n. [G., fr. Skr. [=e]ka one + G. bor, boron,
   E. boron.] (Chem.)
   The name given by Mendelejeff in accordance with the periodic
   law, and by prediction, to a hypothetical element then
   unknown, but since discovered and named scandium; -- so
   called because it was a missing analogue of the boron group.
   See Scandium.
   [1913 Webster]

WordNet (r) 3.0 (2006):

scandium
    n 1: a white trivalent metallic element; sometimes classified in
         the rare earth group; occurs in the Scandinavian mineral
         thortveitite [syn: scandium, Sc, atomic number 21]

The Elements (07Nov00):

scandium
Symbol: Sc
Atomic number: 21
Atomic weight: 44.956
Rare soft silvery metallic element belonging to group 3 of the periodic
table. There are ten isotopes, nine of which are radioactive and have
short half-lives. Predicted in 1869 by Mendeleev, isolated by Nilson in
1879.