The Collaborative International Dictionary of English v.0.48:

Graduation \Grad"u*a"tion\, n. [LL. graduatio promotion to a
   degree: cf. F. graduation division into degrees.]
   [1913 Webster]
   1. The act of graduating, or the state of being graduated;
      as, graduation of a scale; graduation at a college;
      graduation in color; graduation by evaporation; the
      graduation of a bird's tail, etc.
      [1913 Webster]

   2. The marks on an instrument or vessel to indicate degrees
      or quantity; a scale.
      [1913 Webster]

   3. The exposure of a liquid in large surfaces to the air, so
      as to hasten its evaporation.
      [1913 Webster]

WordNet (r) 3.0 (2006):

graduation
    n 1: the successful completion of a program of study
    2: an academic exercise in which diplomas are conferred [syn:
       commencement, commencement exercise, commencement
       ceremony, graduation, graduation exercise]
    3: a line (as on a vessel or ruler) that marks a measurement;
       "the ruler had 16 graduations per inch"
    4: the act of arranging in grades [syn: gradation,
       graduation]

Moby Thesaurus II by Grady Ward, 1.0:

48 Moby Thesaurus words for "graduation":
   advance, advancement, aggrandizement, baccalaureate service, boost,
   celebration, ceremonial, ceremony, commencement, convocation,
   elevation, empty formality, ennoblement, exaltation, exercise,
   exercises, formal, formality, function, gradation, grading,
   graduation exercises, inaugural, inauguration, initiation,
   knighting, liturgy, mummery, observance, office, passing,
   pay raise, performance, preferment, promotion, raise,
   religious ceremony, rise, rite, rite de passage, rite of passage,
   ritual, service, shading, solemnity, solemnization, upgrading,
   upping