The Collaborative International Dictionary of English v.0.48:

Armistice \Ar"mis*tice\, n. [F. armistice, fr. (an assumed word)
   L. armistitium; arma arms + stare, statum (combining form,
   -stitum), to stand still.]
   A cessation of arms for a short time, by convention; a
   temporary suspension of hostilities by agreement; a truce.
   [1913 Webster]

WordNet (r) 3.0 (2006):

armistice
    n 1: a state of peace agreed to between opponents so they can
         discuss peace terms [syn: armistice, cease-fire,
         truce]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "armistice":
   Pax Dei, Pax Romana, Peace of God, breathing spell, buffer zone,
   cease-fire, cooling-off period, demilitarized zone, hollow truce,
   modus vivendi, neutral territory, pacification, pax in bello,
   peace, stand-down, suspension of hostilities,
   temporary arrangement, treaty of peace, truce