English▸ noun a small barrel, especially one of less than 30 gallons or (in the UK) 10 gallons.
▪ a pressurized metal barrel with a valve at one end, used to store and dispense beer or other carbonated drinks:
beer is delicious pumped from a keg.
– ORIGIN early 17th century : variant of Scots and US dialect cag, from Old Norse kaggi.