from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A silvery, soft, ductile metallic element that occurs chiefly in columbite-tantalite and is used in steel alloys, arc welding, and superconductivity research. Atomic number 41; atomic weight 92.906; melting point 2,468°C; boiling point 4,927°C; specific gravity 8.57; valence 2, 3, 5. See Table at element.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a metallic chemical element (symbol Nb) with an atomic number of 41.
from the GNU version of the Collaborative International Dictionary of English
- n. The chemical element of atomic number 41. Chemical symbol Nb. Atomic weight 92.91. Previously called columbium. See also columbium.
from The Century Dictionary and Cyclopedia
- n. Chemical symbol, Nb; atomic weight, 94. A metal of steel-gray color and brilliant luster.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a soft grey ductile metallic element used in alloys; occurs in niobite; formerly called columbium
After Niobe (so called because it is extracted from tantalite).(American Heritage® Dictionary of the English Language, Fourth Edition)
After Niobe, because of the element's affinity with tantalum. (Wiktionary)