angle stop

:  a small valve often used in household plumbing that is placed where a pipe changes directions at a right angle :  angle valve The little valves under the sink that are used to turn the water off to the faucet are called angle stops. The problem with these is that it takes forever to shut them off, and once turned off, they usually leak. — Morris Carey et al., Springfield (Massachusetts) Sunday Republican, 30 July 2006