A hot tub, also known as a spa or jacuzzi, is a self-contained, heated water vessel designed for relaxation and therapeutic purposes. Typically made of acrylic or fiberglass, it is equipped with water jets that provide a soothing and massaging effect when submerged. Hot tubs are often enjoyed outdoors and offer a relaxing environment for socializing, easing muscle tension, and promoting overall well-being. They are commonly used for leisure, stress relief, and hydrotherapy.