Definition: Like a spa, a hot tub has built-in jets to provide warmth, relaxation and a massage-effect on people's muscles and joints. They both are used for therapeutic reasons and socialization. In the early days -- the late 1960s, early 1970s -- hot tubs were made from wood, including cedar, redwood, cypress, teak or a composite. In the mid-1970s, the technologically advanced portable acrylic spas were introduced, replacing the wooden tubs in popularity.

Today, the terms hot tub and spa are used interchangeably. The word "spa" is often associated with a health resort destination or a commercial establishment where patrons can get aesthetic services, massages, facials, etc. Thus, the term hot tub is more specific in describing that hot, bubbly tub, and has experienced a resurgence in usage to distinguish it from a day spa.

Small hot tubs measure about 3-4 feet high by 5 feet across and hold approximately 500 gallons of water. Larger hot tubs are around 4-5 feet high and 6 feet in diameter. They hold about 850 gallons of water.

Remember Will Ferrell and Rachel Dratch's "hot tub luh-vahs" on Saturday Night Live? They often hung out at the Welshley Arms Motel's hot tub, often harrassing other guests.

Also Known As: Spa, wooden spa, Jacuzzi

Common Misspellings: hottub, hotub

Examples: After injuring her shoulder, Veronica found it therapeutic to soak in a hot tub with a massaging jet system.