The Collaborative International Dictionary of English v.0.48:

Centennial \Cen*ten"ni*al\, n.
   The celebration of the hundredth anniversary of any event; a
   centenary. [U. S.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Centennial \Cen*ten"ni*al\, a. [L. centum a hundred + annus
   year.]
   1. Relating to, or associated with, the commemoration of an
      event that happened a hundred years before; as, a
      centennial ode.
      [1913 Webster]

   2. Happening once in a hundred years; as, centennial jubilee;
      a centennial celebration.
      [1913 Webster]

   3. Lasting or aged a hundred years.
      [1913 Webster]

            That opened through long lines
            Of sacred ilex and centennial pines.  --Longfellow.
      [1913 Webster]

WordNet (r) 3.0 (2006):

centennial
    adj 1: of or relating to or completing a period of 100 years;
           "centennial celebration" [syn: centennial, centenary]
    n 1: the 100th anniversary (or the celebration of it) [syn:
         centennial, centenary]

Moby Thesaurus II by Grady Ward, 1.0:

89 Moby Thesaurus words for "centennial":
   C, anniversary, annual, annual holiday, biannual, bicentenary,
   bicentennial, biennial, bimonthly, birthday, bissextile day,
   biweekly, catamenial, cental, centare, centenarian, centenary,
   centennium, centesimal, centigrado, centigram, centimeter,
   centipede, centistere, centred, centref, centrev, centumvir,
   centumvirate, centuple, centuplicate, centurial, centurion,
   century, commemoration, cwt, daily, decennial, diamond jubilee,
   diurnal, fortnightly, golden wedding anniversary, gross,
   hebdomadal, hecatomb, holy days, hourly, hundred, hundredfold,
   hundredth, hundredweight, immovable feast, jubilee, leap year,
   long hundred, menstrual, momentary, momently, monthly, name day,
   natal day, octennial, one C, quadrennial, quarterly,
   quasquicentennial, quincentenary, quincentennial, quinquennial,
   quotidian, secular, semestral, semiannual, semimonthly, semiweekly,
   semiyearly, septennial, sesquicentenary, sesquicentennial,
   sextennial, silver wedding anniversary, tercentenary,
   tercentennial, tertian, tricennial, triennial, wedding anniversary,
   weekly, yearly



U.S. Gazetteer Places (2000):

Centennial, WY -- U.S. Census Designated Place in Wyoming
   Population (2000):    191
   Housing Units (2000): 295
   Land area (2000):     10.024372 sq. miles (25.963003 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    10.024372 sq. miles (25.963003 sq. km)
   FIPS code:            13440
   Located within:       Wyoming (WY), FIPS 56
   Location:             41.297981 N, 106.137614 W
   ZIP Codes (1990):     82055
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Centennial, WY
    Centennial