Dictionary entry

Columbium

Webster's Dictionary 1913

Co‐lum″bi‐um (?), n. [NL., fr. Columbia America.] (Chem.) A rare element of the vanadium group, first found in a variety of the mineral columbite occurring in Connecticut, probably at Haddam. Atomic weight 94.2. Symbol Cb or Nb. Now more commonly called niobium.