Source : Webster's Revised Unabridged Dictionary (1913)

Back \Back\, v. i. [imp. & p. p. {Backed}; p. pr. & vb. n.
   {Backing}.]
   1. To get upon the back of; to mount.

            I will back him [a horse] straight.   --Shak.

   2. To place or seat upon the back. [R.]

            Great Jupiter, upon his eagle backed, Appeared to
            me.                                   --Shak.

   3. To drive or force backward; to cause to retreat or recede;
      as, to back oxen.

   4. To make a back for; to furnish with a back; as, to back
      books.

   5. To adjoin behind; to be at the back of.

            A garden . . . with a vineyard backed. --Shak.

            The chalk cliffs which back the beach. --Huxley.

   6. To write upon the back of; as, to back a letter; to
      indorse; as, to back a note or legal document.

   7. To support; to maintain; to second or strengthen by aid or
      influence; as, to back a friend. ``Parliament would be
      backed by the people.'' --Macaulay.

            Have still found it necessary to back and fortify
            their laws with rewards and punishments. --South.

            The mate backed the captain manfully. --Blackw. Mag.

   8. To bet on the success of; -- as, to back a race horse.

   {To back an anchor} (Naut.), to lay down a small anchor ahead
      of a large one, the cable of the small one being fastened
      to the crown of the large one.

   {To back the field}, in horse racing, to bet against a
      particular horse or horses, that some one of all the other
      horses, collectively designated ``the field'', will win.
      

   {To back the oars}, to row backward with the oars.

   {To back a rope}, to put on a preventer.

   {To back the sails}, to arrange them so as to cause the ship
      to move astern.

   {To back up}, to support; to sustain; as, to back up one's
      friends.

   {To back a warrant} (Law), is for a justice of the peace, in
      the county where the warrant is to be executed, to sign or
      indorse a warrant, issued in another county, to apprehend
      an offender.

   {To back water} (Naut.), to reverse the action of the oars,
      paddles, or propeller, so as to force the boat or ship
      backward.

Backing \Back"ing\, n.
   1. The act of moving backward, or of putting or moving
      anything backward.

   2. That which is behind, and forms the back of, anything,
      usually giving strength or stability.

   3. Support or aid given to a person or cause.

   4. (Bookbinding) The preparation of the back of a book with
      glue, etc., before putting on the cover.

Source : WordNet®

backing
     n 1: the act of providing approval and support; "his vigorous
          backing of the conservatives got him in trouble with
          progressives" [syn: {backup}, {championship}, {patronage}]
     2: something forming a back that is added for strengthening
        [syn: {mount}]
     3: financial resources provided to make some project possible;
        "the foundation provided support for the experiment" [syn:
         {support}, {financial support}, {funding}, {financial
        backing}]