The Collaborative International Dictionary of English v.0.48:

Widespread \Wide"spread`\, a.
   Spread to a great distance; widely extended; extending far
   and wide; as, widespread wings; a widespread movement.
   [1913 Webster]

WordNet (r) 3.0 (2006):

widespread
    adj 1: widely circulated or diffused; "a widespread doctrine";
           "widespread fear of nuclear war"
    2: distributed over a considerable extent; "far-flung trading
       operations"; "the West's far-flung mountain ranges";
       "widespread nuclear fallout" [syn: far-flung, widespread]

Moby Thesaurus II by Grady Ward, 1.0:

106 Moby Thesaurus words for "widespread":
   accepted, ample, amplitudinous, broad, broadcast, capacious,
   commodious, conformable, consuetudinary, conventional, current,
   customary, deep, deltoid, diffuse, discrete, dispersed, dispread,
   disseminated, dissipated, distributed, established, everyday,
   expansive, extended, extending, extensive, familiar, fan-shape,
   fan-shaped, fanlike, fanned, fanning, far-embracing, far-extending,
   far-flung, far-flying, far-going, far-ranging, far-reaching,
   flabelliform, flared, flaring, generally accepted, indiscriminate,
   infinite, large-scale, liberal, normal, obtaining, open, ordinary,
   outspread, outstretched, patulous, popular, prescribed,
   prescriptive, prevalent, rampant, received, regnant, regular,
   regulation, rife, roomy, ruling, scattered, set, spacious, sparse,
   splay, splayed, splaying, sporadic, spraddled, spraddling,
   sprangled, sprangling, sprawling, sprawly, spread, spreading,
   standard, stock, straggling, straggly, stretched-out, strewn,
   strown, sweeping, time-honored, traditional, unfolded, usual, vast,
   voluminous, wholesale, wide, wide-extended, wide-extending,
   wide-open, wide-ranging, wide-reaching, wide-stretching, wonted