The Collaborative International Dictionary of English v.0.48:

Ovation \O*va"tion\, n. [L. ovatio, fr. ovare to exult, rejoice,
   triumph in an ovation; cf. Gr. ? to shout: cf. F. ovation.]
   1. (Rom. Antiq.) A lesser kind of triumph allowed to a
      commander for an easy, bloodless victory, or a victory
      over slaves.
      [1913 Webster]

   2. Hence: An expression of popular homage; the tribute of the
      multitude to a public favorite.
      [1913 Webster]

            To rain an April of ovation round
            Their statues.                        --Tennyson.
      [1913 Webster]

   3. Especially: A prolonged applause for a person of group
      after a speech or performance.
      [PJC]

   standing ovation a prolonged applause during which the
      audience stands as a sign of special appreciation or
      admiration.
      [PJC]

WordNet (r) 3.0 (2006):

ovation
    n 1: enthusiastic recognition (especially one accompanied by
         loud applause) [syn: ovation, standing ovation]

Moby Thesaurus II by Grady Ward, 1.0:

56 Moby Thesaurus words for "ovation":
   acclaim, acclamation, anniversaries, applause, big hand,
   burst of applause, celebrating, celebration, ceremony, cheer,
   cheering, cheers, clap, clapping, clapping of hands, commemoration,
   dressing ship, eclat, encore, fanfare, fanfaronade, festivity,
   flourish of trumpets, hand, handclap, handclapping, holiday,
   jubilee, kudos, laudation, marking the occasion, memorialization,
   memory, observance, plaudit, plaudits, popularity, praise,
   rejoicing, religious rites, remembrance, revel, rite,
   ritual observance, round of applause, salute, salvo,
   solemn observance, solemnization, testimonial, testimonial banquet,
   testimonial dinner, thunder of applause, toast, tribute, triumph



The Devil's Dictionary (1881-1906):

OVATION, n.  n ancient Rome, a definite, formal pageant in honor of
one who had been disserviceable to the enemies of the nation.  A
lesser "triumph."  In modern English the word is improperly used to
signify any loose and spontaneous expression of popular homage to the
hero of the hour and place.

    "I had an ovation!" the actor man said,
        But I thought it uncommonly queer,
    That people and critics by him had been led
            By the ear.

    The Latin lexicon makes his absurd
        Assertion as plain as a peg;
    In "ovum" we find the true root of the word.
            It means egg.
                                                          Dudley Spink