The Collaborative International Dictionary of English v.0.48:

Inauguration \In*au`gu*ra"tion\, n. [L. inauguratio a beginning:
   cf. F. inauguration.]
   [1913 Webster]
   1. The act of inuagurating, or inducting into office with
      solemnity; investiture by appropriate ceremonies.
      [1913 Webster]

            At his regal inauguration, his old father resigned
            the kingdom to him.                   --Sir T.
                                                  Browne.
      [1913 Webster]

   2. The formal beginning or initiation of any movement, course
      of action, etc.; as, the inauguration of a new system, a
      new condition, etc.
      [1913 Webster]

WordNet (r) 3.0 (2006):

inauguration
    n 1: the act of starting a new operation or practice; "he
         opposed the inauguration of fluoridation"; "the startup of
         the new factory was delayed by strikes" [syn:
         inauguration, startup]
    2: the ceremonial induction into a position; "the new president
       obviously enjoyed his inauguration" [syn: inauguration,
       inaugural]

Moby Thesaurus II by Grady Ward, 1.0:

85 Moby Thesaurus words for "inauguration":
   accedence, acceptance, accession, admission, admittance, anchorage,
   baccalaureate service, baptism, celebration, ceremonial, ceremony,
   colonization, coming out, commencement, constitution, convocation,
   coronation, curtain raiser, debut, effectuation, embarkation,
   embarkment, empty formality, enlistment, enrollment, enthronement,
   establishment, exercise, exercises, first appearance, fixation,
   floating, flotation, formal, formality, formation, foundation,
   function, graduation, graduation exercises, immission, inaugural,
   inaugural address, inception, induction, initiation, installation,
   installment, instatement, institution, introduction, intromission,
   investiture, launching, liturgy, lodgment, maiden speech,
   materialization, mooring, mummery, observance, office, opener,
   ordination, organization, peopling, performance, placement,
   plantation, population, preliminary, realization,
   religious ceremony, rite, rite de passage, rite of passage, ritual,
   service, setting-up, settlement, settling, solemnity,
   solemnization, taking office, unveiling