40-ouncer colloquial; 40-ouncer, forty-ouncer, forty ouncer DCHP-2 (February 2016)
n. — slang, informal
a bottle of 40 fluid ounces of liquor.
Type: 5. Frequency — In Canada, spirits are sold in 40-ounce containers. While in the US bottles of the same size are sold as well, the term is nearly twice as frequent in Canadian English as in American English. The spelling with the numeral 40 is more common compared with forty.
See also COD-2, which marks the term "Cdn slang".
See also: two-six
- In spoken language often just referred to as "a forty" (see 2014 quotation).
Images:

Chart 1: Internet Domain Search, 21 Sep. 2012