A bidet is a bathroom fixture designed to wash and clean the genitalia, perineum, inner buttocks, and anus. It is a low-to-the-ground wash basin near the toilet that has hot and cold water faucets that control a stream of fresh water that flows from below. The modern variety has a plumbed-in water supply and a drainage opening, and is thus a plumbing fixture subject to local regulations. The word "bidet" is a French loanword meaning "pony" due to the straddling position adopted in its usage.

There are different types of bidets, including standalone bidets, bidet showers, and bidet toilet seats. Standalone bidets are like wash-basins that are filled with clean water and may be used for many other purposes such as washing feet. Bidet showers are usually placed in a holster on the wall or toilet tank and are multi-purpose tools that can be used for rinsing down shower walls, bathing pets in the tub, or even as diaper sprayers for cleaning cloth diapers. Bidet toilet seats are high-end seats that have the capability of spraying water the same way the standalone bidet can.

Bidets are primarily used to clean oneself after using the toilet, and they offer great advantages to personal hygiene since users can clean themselves more thoroughly than with toilet paper alone. Bidets encourage regular washing, as users do not have to embark on a full-scale shower or bath to get clean. Also, bidets save water and reduce reliance on toilet paper.

To use a bidet, one can sit on the bidet and use the water stream to clean the genitalia, perineum, inner buttocks, and anus. Some bidets have a vertical jet intended to give easy access for washing and rinsing the perineum and anal area. Bidets are common bathroom fixtures in the Arab world and in some parts of Europe, and they are slowly becoming essential parts of modern American bathrooms.