WordNet (r) 3.0 (2006):

ambience
    n 1: a particular environment or surrounding influence; "there
         was an atmosphere of excitement" [syn: atmosphere,
         ambiance, ambience]
    2: the atmosphere of an environment [syn: ambiance,
       ambience]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "ambience":
   alentours, ambient, ambit, atmosphere, borderlands, circle,
   circuit, circumambiencies, circumjacencies, circumstances, climate,
   compass, context, entourage, environing circumstances, environment,
   environs, gestalt, habitat, medium, milieu, mise-en-scene,
   neighborhood, outposts, outskirts, perimeter, periphery, precincts,
   purlieus, situation, suburbs, surroundings, total environment,
   vicinage, vicinity