A bayonet connection, also called bayonet lock or bayonet mount, is a type of quick coupling and fixing mechanism between the intercorresponding surfaces of two parts or devices.

One of them, called "male", has one or more pins or projections that adjust to the receiving or "female" surface, where grooves and a spring maintain the clamping force.

To couple the two surfaces, it is necessary to align and fit by pressing the projections of the male surface with the indentations of the female surface. Once the pins reach the path or stop of the slots, both surfaces are turned in the opposite direction so that the protrusion or pin is guided towards a perpendicular slot arranged to prevent its misalignment and which, thanks to the internal spring, is kept under pressure. To uncouple it, the user must perform the opposite movement, that is, press so that the spring releases from the position perpendicular to the male surface and rotates in the opposite direction.

The strength of the closure depends on the resistance of the material of the pins used, so it may be less effective than other types of fixing systems, although it stands out for its speed and the fact that it does not allow cross unscrewing.

The locking mechanism was originally developed to allow quick adjustment of the weapon's bayonet over the end of the rifle or rifle. Later, it was adapted in photography to mount "Lens (photography)" lenses on the camera body.

Various types of electrical connectors, including audio, video, and data processing wiring applications, use the bayonet style, such as BNC, C, and ST connectors.

Some halogen type lamps that work at 230/240 volts use the so-called B closure in countries that follow the United Kingdom standards, along with the E closure, more common in the United States, Japan and other countries, its frequent use for lighting devices in automobiles and other types of light indicators.

In industries that require fluid engineering and mechanics, the bayonet closure is used in devices that need an intermediate level of fluid tightness at low or medium pressure.

The bayonet thread system was used by the Mayan Civilization during the Late Classic period of their culture. There is material evidence such as the Río Azul chocolate maker "Río Azul (site)"), found in royal tomb #19 of that pre-Hispanic city, which used a very sophisticated screw cap system for the century AD. C. The vessel was found in 1984. The vessel was found in 1984.