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.
- undergo
- undergrad
- undergraduate
- underground
- Underground Railroad
- undergrown
- undergrowth
- underhair
- underhand
- underhanded
- underhandedly
- underhandedness
- under hat
- underhung
- underinsurance
- underinsured
- under/in the circumstances
- underived
- underkill
- underlaid
- underlain
- underlay
- underlay
- underlayment
- underlet