An instrumentality that connects WordNet 3.0 & Open English WordNet

Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. Wikipedia

A device for joining electrical circuits together Wikipedia Disambiguation

Electro-mechanical device used to connect electrical parts Wikidata

That which connects. Wiktionary

A device (or, more precisely, a mating pair of devices, often a plug and a socket) for connecting together two wires, cables, or hoses, allowing electricity or fluid to flow but also allowing easy disconnection and reconnection when necessary. Wiktionary

Mating pair of devices. Wiktionary (translation)