The term MUD-BATH SETTING is a crossword solution that consists of three letters: SPA. A SPA is a place where people go to relax and receive treatments such as massages, facials, and mud baths. A mud bath setting is a type of SPA treatment that involves soaking in a tub filled with warm mud. The mud is said to have healing properties and can help to detoxify the body. It is also believed to improve circulation and reduce stress.