from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A tap or valve used to draw off water (or other liquid) from the lowest part of a tank, boiler etc.
Sorry, no etymologies found.
Put a hose on the draincock at the bottom of the tank and run it to the drain; the drain must be below the tank so it can work by gravity.
Note to customers: When operating the compressor be sure the draincock is closed and the quick disconnect is not stuck.