san·a·to·ri·um 
(săn′ə-tôrē-əm)
(săn′ə-tôrē-əm)n. pl. san·a·to·ri·ums or san·a·to·ri·a (-tôrē-ə)
1. An institution for the treatment of chronic diseases or for medically supervised recuperation.
2. A resort for improvement or maintenance of health, especially for convalescents. Also called sanitarium.
[From neuter of Late Latin sānātōrius, curative, from Latin sānātus, past participle of sānāre, to heal, from sānus, healthy.]