The Collaborative International Dictionary of English v.0.48:

Enlargement \En*large"ment\, n.
   1. The act of increasing in size or bulk, real or apparent;
      the state of being increased; augmentation; further
      extension; expansion.
      [1913 Webster]

   2. Expansion or extension, as of the powers of the mind;
      ennoblement, as of the feelings and character; as, an
      enlargement of views, of knowledge, of affection.
      [1913 Webster]

   3. A setting at large, or being set at large; release from
      confinement, servitude, or distress; liberty.
      [1913 Webster]

            Give enlargement to the swain.        --Shak.
      [1913 Webster]

   4. Diffusiveness of speech or writing; expatiation; a wide
      range of discourse or argument.
      [1913 Webster]

            An enlargement upon the vices and corruptions that
            were got into the army.               --Clarendon.
      [1913 Webster]

WordNet (r) 3.0 (2006):

enlargement
    n 1: the act of increasing (something) in size or volume or
         quantity or scope [syn: expansion, enlargement] [ant:
         contraction]
    2: the state of being enlarged
    3: a discussion that provides additional information [syn:
       expansion, enlargement, elaboration]
    4: a photographic print that has been enlarged [syn:
       enlargement, blowup, magnification]

Moby Thesaurus II by Grady Ward, 1.0:

173 Moby Thesaurus words for "enlargement":
   Ditto copy, Photostat, Xerox, Xerox copy, access, accession,
   accomplishment, accretion, accrual, accruement, accumulation,
   addition, adjunct, advance, advancement, aggrandizement,
   aggravation, ampliation, amplification, annoyance, appreciation,
   ascent, augmentation, ballooning, ballyhoo, big talk, bloating,
   blossoming, blowing up, blowup, blueprint, boom, boost, broadening,
   buildup, burlesque, caricature, contact print, contact printing,
   contentiousness, crescendo, cyanotype, deepening,
   deliberate aggravation, deployment, deterioration, development,
   developmental change, dilatation, dilation, dispersion, edema,
   elaboration, elevation, embittering, embitterment, enhancement,
   evolution, evolutionary change, evolvement, evolving, exacerbation,
   exaggerating, exaggeration, exasperation, excess, exorbitance,
   expansion, expatiation, explication, extension, extravagance,
   extreme, fanning out, flare, flood, flowering, furtherance, gain,
   glossy, gradual change, grandiloquence, greatening, growth, gush,
   hectograph copy, heightening, hike, hiking, hologram, huckstering,
   hyperbole, hyperbolism, impress, impression, increase, increment,
   inflation, inordinacy, intensification, irritation, jump,
   lantern slide, leap, magnification, matte, maturation, microcopy,
   microprint, mimeograph copy, mounting, multiplication,
   natural development, natural growth, negative, nonviolent change,
   offprint, overemphasis, overestimation, overkill, overstatement,
   photocopy, photograph, photogravure, photostatic copy, positive,
   print, prodigality, productiveness, profuseness, progress,
   progression, projection printing, proliferation, proof,
   provocation, puffery, puffing up, raise, raising, reprint,
   ripening, rise, semi-matte, sensationalism, sharpening, slide,
   snowballing, souring, splay, spread, spreading, stat, stretching,
   superlative, surge, swelling, tall talk, touting, transparency,
   travesty, tumescence, unfolding, up, upping, upsurge, upswing,
   uptrend, upturn, waxing, widening, working-out, worsening