Green’s Dictionary of Slang

bong n.1

also bhong, bongo
[Thai baung, lit. ‘cylindrical wooden tube’]

(US drugs, a kind of bowl-shaped water-pipe used for smoking marijuana (the specifics vary as to the maker); thus Aus.) bongineering, bongology, the construction of such pipes; bong hit, a puff on such a pipe.

Marijuana Rev. Jan.–June 18: Many thanks to Scott Bennett [...] for the beautiful special bong he made for my pipe collection.
[Aus]Lette & Carey Puberty Blues 97: We smoked the dope in a bong. This is a kind of peace pipe made from a milk bottle with two bits of garden hose stuck in the neck. You stuffed one hose with marijuana, lit it and dragged furiously on the other.
[US]D.E. Miller Bk of Jargon 339: bhong: A pipe for smoking marijuana.
[Aus]Tracks (Aus.) Dec. 3: In those three years [of smoking cannabis] I have never, ever cringed for a bong [Moore 1993].
[US]A. Rodriguez Spidertown (1994) 138: He was going to roll a joint, but she suggested using Firebug’s bong.
[UK]J. Poller Reach 83: I bump into [...] a man I’ve never met before doing bong hits on the kitchen floor.
Stoners’ Dict. [Internet] Bongo [AU] – Alternative term to bong.
[Aus]L. Redhead Peepshow [ebook] Her wizard-shaped bong was absent from its usual place on the coffee table.
[UK]B. Hare Urban Grimshaw 84: Two teenage girls were [...] smoking from a homemade bong.
[Aus] L. Jose ‘Underhooks’ in Crime Factory: Hard Labour [ebook] Bentley took a hit from his bong.
[Aus]‘First Dog on the Moon’ in crikey.com.au 2 July [Internet] I went to this party this one time and there were 15 bongs there at once.
[UK]J. Fagan Panopticon (2013) 288: He passes me a wee bong [...] I drag hard on it — and my spine goes numb.

In compounds

bonghead (n.)

a habitual smoker of cannabis.

[SA]Mail & Guardian (Johannesburg) 24 Sept. [Internet] No, I am not a zol monkey. This is not a throwdown from a bonghead.

In phrases

bong on (v.)

(Aus.) to smoke a bong.

B. Hudson 1st Aus. Dict. Vulgarities & Obscenities n.p.: Bong. A water pipe for smoking marijuana. To indulge in this habit is to bong on.
[Aus]Sydney Morn. Herald 12 Sept. [Internet] With the new ingredient available for slicing, dicing and baking, we predict lamington drives will be far more exciting. Bong on, ladies.