Source : Webster's Revised Unabridged Dictionary (1913)

Swab \Swab\, v. t. [imp. & p. p. {Swabbed}; p. pr. & vb. n.
   {Swabbing}.] [See {Swabber}, n.]
   To clean with a mop or swab; to wipe when very wet, as after
   washing; as, to swab the desk of a ship. [Spelt also {swob}.]

Swab \Swab\, n. [Written also swob.]
   1. A kind of mop for cleaning floors, the desks of vessels,
      etc., esp. one made of rope-yarns or threads.

   2. A bit of sponge, cloth, or the like, fastened to a handle,
      for cleansing the mouth of a sick person, applying
      medicaments to deep-seated parts, etc.

   3. (Naut.) An epaulet. [Sailor's Slang] --Marryat.

   4. A cod, or pod, as of beans or pease. [Obs.] --Bailey.

   5. A sponge, or other suitable substance, attached to a long
      rod or handle, for cleaning the bore of a firearm.

Source : WordNet®

swab
     n 1: implement consisting of a small piece of cotton that is used
          to apply medication or cleanse a wound or obtain a
          specimen of a secretion
     2: cleaning implement consisting of absorbent material fastened
        to a handle; for cleaning floors [syn: {swob}, {mop}]
     v 1: wash with a swab or a mop; "swab the ship's decks" [syn: {swob}]
     2: apply (usually a liquid) to a surface; "dab the wall with
        paint" [syn: {dab}, {swob}]
     [also: {swabbing}, {swabbed}]

Source : Free On-Line Dictionary of Computing

swab
     
        /swob/ The {PDP-11} swap byte instruction mnemonic, as
        immortalised in the {dd} option "conv=swab".
     
        1. To solve the {NUXI problem} by swapping bytes in a file.
     
        2.  The program in V7 Unix used to perform this action, or
        anything functionally equivalent to it.
     
        See also {big-endian}, {little-endian}, {middle-endian},
        {bytesexual}.
     
        [{Jargon File}]