Green’s Dictionary of Slang

1. (drugs) cocaine, spec. pieces that are smaller than average.

1911		S.F. Call 7 May 3/5: ‘Flake’ is powdered cocaine. the victim inhales it like snuff .
1922		E. Murphy Black Candle 52: Cocaine is sold to school-children as ‘coke’ or ‘flake’.
1965		B. Jackson Get Your Ass in the Water (1974) 206: He sprinkled my tree with flakes of cocaine.
1969		R.R. Lingeman Drugs from A to Z (1970).
1976		R. Sabbag Snowblind (1978) 193: ‘And this is my product,’ pointing to the rock [...] ‘the purest flake on the street’.
1983		Grandmaster & Mellie Mel ‘White Lines’ 🎵 Dust, flake or rocks?
1991		L. Bing Do or Die (1992) xv: The good-natured, street-smart guy who used to drop by the house with the weekend supply of Bolivian flake.
2002		Fabian & Byrne Out of Time (ms.) 172: With half-a-gram of Peruvian flake in my pocket and fraught with nervous energy I made my way to Maddie’s terraced house.
2008		R. Price Lush Life 367: The flake brought tears to his eyes .
2011		J.J. Connolly Viva La Madness 12: The concierge service could provide the best flake cocaine on that whole bit of coast.
2013		T. Dorsey Riptide Ultra-Glide 8: Coke, blow, flake, fluff, snow, marching dust, weasel powder, white death [etc].
2017		67 ‘Waps’ 🎵 Yeah, bro creating the funkyhouse and my brudda C got the flake.

2. (drugs) heroin.

1953

Kramer & Karr Teen-Age Gangs 147: I have often thought [...] how this increased our consumption of reefers and flakes from the tall white horse.

3. (drugs) in pl., phencyclidine.

1979		H. Feldman et al. Angel Dust 124: The large number of street names it has been accorded over the years: [...] flakes.
2001		ONDCP Street Terms 9: Flakes — PCP.

4. (Aus.) shark meat, esp. as sold in fish ’n’ chip shops.

1985		B. Humphries Traveller’s Tool 79: On Fridays you could count on a good serve of flake (or shark meat), deep-fried in batter.
1987		M. Bail Holden’s Performance (1989) 250: Shadbolt paused with a lump of flake.