Petcocks

Part of speech: noun

Definitions

1. A type of valve that allows for the release of air or fluid from a system
2. a small, mechanized opening used to control the flow of liquids in pipes
3. a specialized fitting found in automotive or plumbing applications for maintenance tasks

Etymology: "Petcocks" is the plural of "petcock," a small valve used to let air or liquid out of a system, such as a boiler or an engine cylinder. The singular is the one that carries the etymology: it appears to be a compound of "pet," a word of uncertain origin that in English often means a favourite or indulged thing, and "cock," which in this sense refers to a tap or valve controlling flow. The valve is named for its size, the "pet" element signalling something small or diminutive compared with the larger cock it resembles.