Source : Webster's Revised Unabridged Dictionary (1913)

Banker \Bank"er\, n.[See the nouns {Bank} and the verbs derived
   from them.]
   1. One who conducts the business of banking; one who,
      individually, or as a member of a company, keeps an
      establishment for the deposit or loan of money, or for
      traffic in money, bills of exchange, etc.

   2. A money changer. [Obs.]

   3. The dealer, or one who keeps the bank in a gambling house.

   4. A vessel employed in the cod fishery on the banks of
      Newfoundland. --Grabb. J. Q. Adams.

   5. A ditcher; a drain digger. [Prov. Eng.]

   6. The stone bench on which masons cut or square their work.
      --Weale.

Source : WordNet®

banker
     n 1: someone who owns or is an executive in a bank
     2: the person in charge of the bank in a gambling game