hook·up 
(hkŭp′)
(hkŭp′)n.
1. A system or network of electrical circuits or equipment designed to operate together.
2.
a. A configuration of mechanical parts or devices providing a link between a supply source and a user: a gas hookup for a mobile home.
b. A plan or schematic drawing of such a system or such a configuration.
3. Informal A linkage or connection, often between unlikely associates or factors.
4. Informal
a. An act of casual sex.
b. A partner in an act of casual sex.