Source : Webster's Revised Unabridged Dictionary (1913)

Customer \Cus"tom*er\ (k[u^]s"t[u^]m*[~e]r), n. [A doublet of
   customary, a.: cf. LL. custumarius toll gatherer. See
   {Custom}.]
   1. One who collect customs; a toll gatherer. [Obs.]

            The customers of the small or petty custom and of
            the subsidy do demand of them custom for kersey
            cloths.                               --Hakluyt.

   2. One who regularly or repeatedly makes purchases of a
      trader; a purchaser; a buyer.

            He has got at last the character of a good customer;
            by this means he gets credit for something
            considerable, and then never pays for it.
                                                  --Goldsmith.

   3. A person with whom a business house has dealings; as, the
      customers of a bank. --J. A. H. Murray.

   4. A peculiar person; -- in an indefinite sense; as, a queer
      customer; an ugly customer. [Colloq.] --Dickens.

   5. A lewd woman. [Obs.] --Shak.

Source : WordNet®

customer
     n : someone who pays for goods or services [syn: {client}]