Source : Webster's Revised Unabridged Dictionary (1913)

Buffer \Buff"er\ (b[u^]f"[~e]r), n. [Prop a striker. See
   {Buffet} a blow.]
   1. (Mech.)
      (a) An elastic apparatus or fender, for deadening the jar
          caused by the collision of bodies; as, a buffer at the
          end of a railroad car.
      (b) A pad or cushion forming the end of a fender, which
          receives the blow; -- sometimes called {buffing
          apparatus}.

   2. One who polishes with a buff.

   3. A wheel for buffing; a buff.

   4. A good-humored, slow-witted fellow; -- usually said of an
      elderly man. [Colloq.] --Dickens.

Source : WordNet®

buffer
     v 1: add a buffer (a solution); "buffered saline solution for the
          eyes"
     2: protect from impact; "cushion the blow" [syn: {cushion}, {soften}]

buffer
     n 1: an ionic compound that resists changes in its pH
     2: an inclined metal frame at the front of a locomotive to
        clear the track [syn: {fender}, {cowcatcher}, {pilot}]
     3: (computer science) a part of RAM used for temporary storage
        of data that is waiting to be sent to a device; used to
        compensate for differences in the rate of flow of data
        between components of a computer system [syn: {buffer
        storage}, {buffer store}]
     4: a power tool used to buff surfaces [syn: {polisher}]
     5: a cushion-like device that reduces shock due to contact
        [syn: {fender}]
     6: an implement consisting of soft material mounted on a block;
        used for polishing (as in manicuring) [syn: {buff}]

Source : Free On-Line Dictionary of Computing

buffer
     
        1. An area of memory used for storing messages.  Typically, a
        buffer will have other attributes such as an input pointer
        (where new data will be written into the buffer), and output
        pointer (where the next item will be read from) and/or a count
        of the space used or free.  Buffers are used to decouple
        processes so that the reader and writer may operate at
        different speeds or on different sized blocks of data.
     
        There are many different algorithms for using buffers, e.g.
        first-in first-out (FIFO or shelf), last-in first-out (LIFO or
        stack), double buffering (allowing one buffer to be read while
        the other is being written), cyclic buffer (reading or writing
        past the end wraps around to the beginning).
     
        2. An electronic device to provide compatibility between two
        signals, e.g. changing voltage levels or current capability.