The Collaborative International Dictionary of English v.0.48:

Sanitarium \San`i*ta"ri*um\, n. [NL. See Sanitary.]
   A health station or retreat; a sanatorium. "A sanitarium for
   troops." --L. Oliphant.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sanitarium
    n 1: a hospital for recuperation or for the treatment of chronic
         diseases [syn: sanatorium, sanatarium, sanitarium]