The Collaborative International Dictionary of English v.0.48:

Tri- \Tri-\ [Gr. tri- or L. tri-, sometimes through French; akin
   to L. tres three, and E. three. See Three.]
   [1913 Webster]
   1. A prefix meaning three, thrice, threefold; as in
      tricolored, tridentate.
      [1913 Webster]

   2. (Chem.) A prefix (also used adjectively) denoting three
      proportional or combining part, or the third degree of
      that to the name of which it is prefixed; as in
      trisulphide, trioxide, trichloride.
      [1913 Webster]

U.S. Gazetteer Places (2000):

Tri-City, OR -- U.S. Census Designated Place in Oregon
   Population (2000):    3519
   Housing Units (2000): 1409
   Land area (2000):     7.566289 sq. miles (19.596599 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    7.566289 sq. miles (19.596599 sq. km)
   FIPS code:            74650
   Located within:       Oregon (OR), FIPS 41
   Location:             42.991481 N, 123.312353 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Tri-City, OR
    Tri-City
    Tri, OR
    Tri


U.S. Gazetteer Places (2000):

Tri-Lakes, IN -- U.S. Census Designated Place in Indiana
   Population (2000):    3925
   Housing Units (2000): 1652
   Land area (2000):     35.160049 sq. miles (91.064104 sq. km)
   Water area (2000):    0.897983 sq. miles (2.325765 sq. km)
   Total area (2000):    36.058032 sq. miles (93.389869 sq. km)
   FIPS code:            76526
   Located within:       Indiana (IN), FIPS 18
   Location:             41.229009 N, 85.472531 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Tri-Lakes, IN
    Tri-Lakes
    Tri, IN
    Tri