plug

Plug is a term used for several devices and concepts that create or interrupt connections between systems or objects. It can refer to a device that completes an electrical circuit, a seal that blocks a passage, a software extension, or a promotional mention.

An electrical plug is a male connector that attaches to a female receptacle (socket) to supply power. A plug normally has metal conductors (prongs) that fit into matching slots in a socket. Many plugs include a grounding pin or blade for safety. Designs vary by country and application, producing a range of sizes, voltages, and configurations, from household plugs to industrial connectors. The mating of plug and socket is intended to prevent exposure to live conductors when partially inserted, and many systems employ polarization and insulation to reduce risk.

A plug in plumbing is a device used to seal a hole or pipe, such as a drain or test port. Drain plugs may be removable stoppers; other plugs use expanding materials or threaded caps. Plumbing plugs must tolerate the system’s pressure, temperature, and fluid type.

In software, a plug-in (or plugin) is a software component that adds a specific feature to an existing program. Plugins load into a host application to extend functionality without altering core code. Common examples include browser plugins, audio plugins in digital audio workstations, and content management system plugins.

In advertising or media, to plug a product is to promote or mention it, typically within content.