Merriam-Webster Collegiate Dictionary - sanatorium

 noun  (plural -riums or sanatoria)  Etymology: New Latin, from Late Latin, neuter of sanatorius curative, from sanare  Date: 1839  1. an establishment that provides therapy combined with a regimen (as of diet and exercise) for treatment or rehabilitation  2.  a. an institution for rest and recuperation (as of convalescents)  b. an establishment for the treatment of the chronically ill