WordNet (r) 3.0 (2006):

Rotterdam
    n 1: the 2nd largest city in the Netherlands; located in the
         western Netherlands near the North Sea

U.S. Gazetteer Places (2000):

Rotterdam, NY -- U.S. Census Designated Place in New York
   Population (2000):    20536
   Housing Units (2000): 8825
   Land area (2000):     6.930121 sq. miles (17.948929 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    6.930121 sq. miles (17.948929 sq. km)
   FIPS code:            63924
   Located within:       New York (NY), FIPS 36
   Location:             42.782776 N, 73.957261 W
   ZIP Codes (1990):     12303
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Rotterdam, NY
    Rotterdam