The Collaborative International Dictionary of English v.0.48:

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.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "widened":
   accelerated, aggrandized, ampliate, amplified, augmented,
   beefed-up, bloated, boosted, broadened, built-up, crescendoed,
   deepened, elevated, enhanced, enlarged, expanded, extended,
   heightened, hiked, increased, inflated, intensified, jazzed up,
   magnified, multiplied, proliferated, raised, reinforced, spread,
   stiffened, strengthened, swollen, tightened, upped