Green’s Dictionary of Slang

1. (also zoner) a habitual drug user.

1992		J. Mowry Way Past Cool 56: The Friends skated casually [...] dodging the legs of wineheads and zoners sticking from doorways.
1995		(con. 1985–90) P. Bourjois In Search of Respect 26: Caesar [...] was nicknamed ‘C-Zone’ because of the frequency of his drug and alcohol binges.
2013		J. Stahl Happy Mutant Baby Pills 61: I hovered, like some lind of zoner perv.

2. an ounce of (crack) cocaine [play on SE ozone].

1993		K. Scott Monster (1994) 363: ‘What is this, crack?’ ‘Yeah, it’s two zones there for you.’.
2000		Urban Dict. 6 Feb. 🌐 a zone is an ounce.
2014		Young Jeezy ‘What You Say’ 🎵 Gold Rolie on right now, Swear it cost ya boy bout 72 zones.
2019		N. Walker Cherry 253: Mike said, ‘Who is this guy? [...] Is he alright?’ ‘Has been so far, yeah.’ ‘He said a zone?’.