Source : Webster's Revised Unabridged Dictionary (1913)

Widen \Wid"en\, v. t. [imp. & p. p. {Widened}; p. pr. & vb. n.
   {Widening}.]
   To make wide or wider; to extend in breadth; to increase the
   width of; as, to widen a field; to widen a breach; to widen a
   stocking.

Source : WordNet®

widening
     n 1: an increase in width [syn: {broadening}] [ant: {narrowing}]
     2: a part of a road that has been widened to allow cars to pass
        or park [syn: {turnout}]
     3: the act of making something wider [syn: {broadening}] [ant:
        {narrowing}]