The Collaborative International Dictionary of English v.0.48:

Vivarium \Vi*va"ri*um\, n.; pl. E. Vivariums, L. Vivaria.
   [L., fr. vivarius belonging to living creatures, fr. vivus
   alive, living. See Vivid.]
   A place artificially arranged for keeping or raising living
   animals, as a park, a pond, an aquarium, a warren, etc.
   [1913 Webster]

WordNet (r) 3.0 (2006):

vivarium
    n 1: an indoor enclosure for keeping and raising living animals
         and plants and observing them under natural conditions