The Collaborative International Dictionary of English v.0.48:

Intermission \In`ter*mis"sion\, n. [L. intermissio: cf. F.
   intermission. See Intermit.]
   [1913 Webster]
   1. The act or the state of intermitting; the state of being
      neglected or disused; disuse; discontinuance. --B. Jonson.
      [1913 Webster]

   2. Cessation for a time; an intervening period of time; an
      interval; a temporary pause; as, to labor without
      intermission; an intermission of ten minutes.
      [1913 Webster]

            Rest or intermission none I find.     --Milton.
      [1913 Webster]

   3. Specifically: The short period between acts of a play,
      concert, opera, or other public performance when the
      audience may leave their seats for refreshment; -- it
      usually lasts from 10 to 20 minutes.
      [PJC]

   4. (Med.) The temporary cessation or subsidence of a fever;
      the space of time between the paroxysms of a disease.
      Intermission is an entire cessation, as distinguished from
      remission, or abatement of fever.
      [1913 Webster]

   5. Intervention; interposition. [Obs.] --Heylin.

   Syn: Cessation; interruption; interval; pause; stop; rest;
        suspension. See Cessation.
        [1913 Webster]

WordNet (r) 3.0 (2006):

intermission
    n 1: the act of suspending activity temporarily
    2: a time interval during which there is a temporary cessation
       of something [syn: pause, intermission, break,
       interruption, suspension]

Moby Thesaurus II by Grady Ward, 1.0:

107 Moby Thesaurus words for "intermission":
   abeyance, act, afterpiece, bit, breach, break, breath, breather,
   breathing place, breathing space, breathing spell, breathing time,
   caesura, catharsis, cease-fire, cessation, chaser, cigarette break,
   cleansing, cocktail hour, coffee break, cold storage, curtain,
   curtain call, curtain raiser, day off, deliverance, discharge,
   divertimento, divertissement, doldrums, dormancy, downtime, drop,
   emotional release, enforced respite, epilogue, exode, exodus,
   expository scene, finale, fissure, freeing, gap, half time,
   half-time intermission, halt, happy hour, hesitation, hiatus,
   hoke act, holiday, interim, interlude, intermezzo, intermittence,
   interregnum, interruption, interval, introduction, lacuna, lapse,
   latency, layoff, letup, lull, number, off-time, parenthesis, pause,
   plateau, point of repose, prologue, purgation, purge, purging,
   quiescence, quiescency, quiet spell, recess, release, relief,
   remission, removal, reprieve, respite, rest, resting point,
   routine, scene, shtick, sketch, skit, song and dance, spell,
   stand-down, stand-up comedy act, stay, striptease, surcease,
   suspension, tea break, time off, time out, truce, turn, vacation