The Collaborative International Dictionary of English v.0.48:

Metropolis \Me*trop"o*lis\, n. [L. metropolis, Gr. ?, prop., the
   mother city (in relation to colonies); ? mother + ? city. See
   Mother, and Police.]
   [1913 Webster]
   1. The mother city; the chief city of a kingdom, state, or
      country.
      [1913 Webster]

            [Edinburgh] gray metropolis of the North.
                                                  --Tennyson.
      [1913 Webster]

   2. (Eccl.) The seat, or see, of the metropolitan, or highest
      church dignitary.
      [1913 Webster]

            The great metropolis and see of Rome. --Shak.
      [1913 Webster]

   3. Any large city.
      [PJC]

WordNet (r) 3.0 (2006):

metropolis
    n 1: a large and densely populated urban area; may include
         several independent administrative districts; "Ancient Troy
         was a great city" [syn: city, metropolis, urban
         center]
    2: people living in a large densely populated municipality; "the
       city voted for Republicans in 1994" [syn: city,
       metropolis]

Moby Thesaurus II by Grady Ward, 1.0:

81 Moby Thesaurus words for "metropolis":
   Kreis, Stadt, archbishopric, archdiocese, arrondissement,
   art center, bailiwick, banlieue, bishopric, boom town, borough,
   bourg, burg, burgh, canton, capital, capital city, city, commune,
   congressional district, constablewick, conurbation, county,
   departement, diocese, district, duchy, electoral district,
   electorate, exurb, exurbia, faubourg, garment center, ghost town,
   government, greater city, hamlet, hundred, magistracy,
   manufacturing center, market town, medical center, megalopolis,
   metropolitan area, municipality, oblast, okrug, outskirts, parish,
   polis, precinct, principality, province, railroad center, region,
   riding, sheriffalty, sheriffwick, shipping center, shire,
   shopping center, shrievalty, soke, spread city, stake, state,
   suburb, suburbia, territory, tourist center, town, township,
   trade center, urban center, urban complex, urban sprawl, urbs,
   village, ville, wapentake, ward



The Devil's Dictionary (1881-1906):

METROPOLIS, n.  A stronghold of provincialism.


U.S. Gazetteer Places (2000):

Metropolis, IL -- U.S. city in Illinois
   Population (2000):    6482
   Housing Units (2000): 3265
   Land area (2000):     5.005127 sq. miles (12.963220 sq. km)
   Water area (2000):    0.063759 sq. miles (0.165134 sq. km)
   Total area (2000):    5.068886 sq. miles (13.128354 sq. km)
   FIPS code:            48645
   Located within:       Illinois (IL), FIPS 17
   Location:             37.153332 N, 88.725374 W
   ZIP Codes (1990):     62960
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Metropolis, IL
    Metropolis