noun 1.an act or instance of hooking up.
2.an assembly and connection of parts, components, or apparatus into a circuit,
network, machine, or system.
3.the circuit, network, machine, or system so formed.
4.a device or connection, as a plug, hose, or pipe, for conveying electricity, a water supply, etc., from a source to a user: Some campsites have electrical hookups for trailers.
5.Informal. an association, alliance, or cooperative effort: A closer hookup of Caribbean nations would be good for international trade.