Source : Webster's Revised Unabridged Dictionary (1913)

Narrowing \Nar"row*ing\, n.
   1. The act of contracting, or of making or becoming less in
      breadth or extent.

   2. The part of a stocking which is narrowed.

Narrow \Nar"row\, v. t. [imp. & p. p. {Narrowed}; p. pr. & vb.
   n. {Narrowing}.] [AS. nearwian.]
   1. To lessen the breadth of; to contract; to draw into a
      smaller compass; to reduce the width or extent of. --Sir
      W. Temple.

   2. To contract the reach or sphere of; to make less liberal
      or more selfish; to limit; to confine; to restrict; as, to
      narrow one's views or knowledge; to narrow a question in
      discussion.

            Our knowledge is much more narrowed if we confine
            ourselves to our own solitary reasonings. --I.
                                                  Watts.

   3. (Knitting) To contract the size of, as a stocking, by
      taking two stitches into one.

Source : WordNet®

narrowing
     adj 1: becoming gradually narrower; "long tapering fingers";
            "trousers with tapered legs" [syn: {tapered}, {tapering}]
     2: (of circumstances) tending to constrict freedom [syn: {constricting},
         {constrictive}]
     n 1: an instance of becoming narrow
     2: a decrease in width [ant: {widening}]
     3: the act of making something narrower [ant: {widening}]

Source : Free On-Line Dictionary of Computing

narrowing
     
        {Unification} followed by {unfolding}.  The left-hand side of
        a {rule} is unified with some term, resulting in a set of
        variable bindings.  The term is then replaced by the
        right-hand side of the rule with values substituted for {bound
        variable}s.