Definition from Wiktionary, the free dictionary
See also: hookups
They are said to hook up with a washing machine.
hook-ups pl (plural only)
- (colloquial) A pair of miniature valves right next to each other on a wall, connecting through the wall to the household plumbing, used to provide water to a washing machine. (They are usually red and blue, with the red one delivering hot water and the blue one delivering cold water.)
- wikiHow, How to Install a Washing Machine (accessed on 2014-02-09)