IPA: /ˌsænəˈtɔːrɪəm/
KK: /sænəˈtɔrɪəm/
A place where people go to recover their health, especially after being sick or for long-term treatment of illnesses.
After her surgery, she spent several weeks at a sanatorium to regain her strength.
Sanatorium → It is formed from "sanare" (meaning to heal) and the suffix "-orium" (meaning a place for). The word "sanatorium" refers to a place for healing or recovery, typically for those with chronic illnesses.
Think of a place where people go to 'heal' ('sanare') — that's what a sanatorium is, a place for recovery.