an artifact (or system of artifacts) that is instrumental in accomplishing some end

connect, fasten, or put together two or more pieces

plug into an outlet

a connection that fastens things together

the part of a network that connects other networks together

a connection between an electrical device and a large conducting body, such as the earth (which is taken to be at zero voltage)

a connection between a vehicle and the load that it pulls

a device providing a connection between a power source and a user