tantalum \tan"talum\, n. nl. so named on account of the
   perplexity and difficulty encounterd by its discoverer
   ekeberg in isolating it. see tantalus. chem.
   a rare nonmetallic element found in certain minerals, as
   tantalite, samarskite, and fergusonite, and isolated as a
   dark powder which becomes steel-gray by burnishing. symbol
   ta. atomic weight 182.0. formerly called also tantalium.
   1913 webster
see also:
tantalus tantalium