Green’s Dictionary of Slang

1. (US drugs, also oh) an ounce of a narcotic.

1936		D. Maurer ‘Argot of the Und. Narcotic Addict’ Pt 1 in AS XI:2 124/2: o. 1. Among addicts who use the needle it refers to an ‘ounce’ or piece of dope, especially of morphine.
1959		J.E. Schmidt Narcotics Lingo and Lore.
1990		J. Wambaugh Golden Orange (1991) 51: Says he got five ohs for takin on the transportation job.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 128/1: O n. 1 (also Oie) an ounce of marijuana.
2013		K. Koke ‘Fire in the Booth’ 🎵 We’d probably all be broke if [we] don't slang / That’s why I'm shotting O’s on the road fam.
2014		Young Jeezy ‘Me OK’ 🎵 34 a unit, nine hundred a O.
2015		67 ‘Live Corn’ 🎵 I'm still slanging these O’s, running through hoes.

2. (drugs) opium.

1933		D. Maurer ‘Junker Lingo’ in AS VIII:2 27: Opium is referred to specifically as O., mud, or hop, and the addict is known as a hophead, pipe-smoker, or cookie.
1951		W. Burroughs letter 5 May in Harris (1993) 83: Still smoke O once a week. It is different from needle kicks.
1961		Rigney & Smith Real Bohemia 58: It is a member of the opium alkaloid family – which includes opium (called ‘O’).
1970		T. Southern Blue Movie (1974) 206: The ‘long-ago-and-far-away’ glitter in her eyes reflected the double dose of liquid O-meth she had dropped for the occasion.
1973		in C. Browne Body Shop 28: Old men sittin’ round the villes smoking O.
1983		V. Viidikas ‘Island of Gems’ in India Ink (1984) 45: By the second packet of o. we are sweating profusely and being given bowls of cold tea.
1990		(con. early 1950s) J. Ellroy L.A. Confidential 365: Lamar Hinton said Spade smoked opium; Spade played the Lariat Room in Frisco – across from Chrissie Renfro’s place of death. Chrissie died with ‘O’ in her system.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 128/1: O n. [...] 2 opium.
2001		ONDCP Street Terms 16: O — Opium.
2012		(con. 1943) G.S. Manson Coorparoo Blues [ebook] He wanted to smoke the O to kill the pain, but it would slow him down too much.
2021		J. Ellroy Widespread Panic 65: Bela Lugosi and Peter Lorre toked ‘O’.

3. (US drugs) a $50 rock of cocaine.

1985

T.R. Houser Central Sl.

4. (US drugs) an ounce of cannabis.

2012		Chief Keef ‘No Tomorrow’ 🎵 Lotta pound lotta O's / Lotta of bankrolls and clothes.
2019		Headie One ‘Both’ 🎵 Counting up this money from O or money from shows.