Green’s Dictionary of Slang

eighteen n.

(Aus.) an 18-gallon (82-litre) keg of beer.

[Aus]G. Casey It’s Harder for Girls 168: ‘We got an eighteen, and plenty o’ bottles coming over.’.
P. Adam-Smith Folklore of the Australian Railwaymen (1971) 148: We had a squeeze box for music and plenty of singers and two eighteens and a ten and it went well .
[Aus]D. Ireland Glass Canoe (1982) 117: At his benefit night we arranged a few kegs — eighteens — because we were all pretty sad.
T. Robertson Dimboola 105: A cheer went up at the broaching of the second eighteener.
Higgins & Prior Jockey Who Laughed 91: ‘It’s just that they have to make sure that they get rid of the eighteen of beer’.
‘Roy Slaven’ Five South Coast Seasons 9: He then tries to stand up. It’s not easy, let me tell you - an eighteen can put a fair bit of strain on the rod, especially is the bloke has no technique.

In compounds

eighteen things (n.)

(US drugs) half a kilogram (i.e. 18 ounces) of cocaine.

Young Jeezy ‘What You Say’ 🎵 Ya check always right, how can we help you King? / I said, Yea, I can name 18 things OK.