Keg faucet (3)
I believe the answer is:
tap
'keg faucet' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tap that I've seen before include "British faucet" , "Knock gently" , "1dn to get on the phone, perhaps!" , "Knock or draw upon" , "Thread cutter; strike" .)