D defs.my
Entry 1 sense Webster, 1913

niobium

/nīō'bēəm/ · ni·o·bi·um · IPA /naɪˈoʊbiəm/
01 n. The chemical element of atomic number 41. Chemical symbol Nb. Atomic weight 92.91. Previously called columbium. See also Columbium.
  1. 1.
    The chemical element of atomic number 41. Chemical symbol Nb. Atomic weight 92.91. Previously called columbium. See also Columbium.(Chem.) Also: columbium See: Columbium