Green’s Dictionary of Slang

1. a glass of beer, orig. two-thirds of a pint, later around half a pint (but note 1885 which suggests 2 pints).

1884		Eve. Jrnl (Adelaide) 10 June 3/3: It appeared from his own account that this boy had entered a hotel in Norwood and drunk ‘three butchers of beer.’ He did not know exactly how much a ‘butcher’ was – (laughter) – but if it represented a pint, or anything like it, it was evidently far too much for a boy of his years.
1885		Sth Aus. Register (Adelaide) 6 Aug. 6/7: I am creditably informed that if you divide £6 of beer into sixty-nine parts there will be two quarts to each part, and that there is a new measure used at pubs, called a butcher, which contains 2 pints.
1898		E.E. Morris Austral Eng. 73/1: Butcher, n. South Australian slang for a long drink of beer, so-called [it is said] because the men of a certain butchery in Adelaide used this refreshment regularly; cf. ‘porter’ in England.
1900–10		Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] 35: butcher. Adelaide, gradually spreading a glass of beer containing about two-thirds of a pint [...] German origin ‘becher’ a beaker or kind of lidded drinking jug.
1903		Mudgee Guardian (NSW) 10 Dec. 20/3: The controversey [sic] in the newspapers has brought out the fact that the longest 3d beer in Australia is obtainable in Adelaide. It is nick-named ‘a butcher’ from the name of the publican who introduced the peculiar shaped glass or mug.
1910		Bulletin (Sydney) 22 Sept. 10/1: Business is good, nathless, for the Chow likes his beer. Not whisky; beer. The Chow of Brighton can ‘swipe a sleever’ or a ‘butcher’ with the best of ’em.
1920		Smith’s Wkly (Sydney) 3 Jan. 3: [A] witness said he went to a hotel and had a ‘butcher.’ Everyone in S.A. knows that a ‘butcher’ is a long beer.
1944		Sunshine Advocate (Vic) 3 Mar. 4/4: [A] butcher, medium-size beer glass.
1949		D. Walker We Went to Aus. 194: As measures of beer, ‘schooner’ and ‘butcher’ are unknown in England.
1954		Sydney Morn. Herald 8 Nov. 2/4: On further investigation, it turned out that calling for an appropriately named Sydney ‘lady’s waist’ in Adelaide would probably result in being hauled off to gaol for offensive behaviour. The South Australians call it a ‘butcher,’ though the man from Adelaide could not explain why .
1963		R. McGregor-Hastie Compleat Migrant 17: You gotta ask for it in Orstalian, then! [...] You want two butchers or two schooners. Or two ponies.
1972		B. Wannan Folklore of the Aus. Pub 125: Butcher: a 5 oz. glass of beer.
2000		R.G. Barrett Leaving Bondi (2013) [ebook] All Les knew about drinking in South Australia was [...] instead of pots and middies, they drank butcher’s.

2. a 6-ounce (170ml) glass.

1943		Advertiser (Adelaide) 20 Jan. 6/3: Evidently Mr. A. Waddell does not know that the reputed pint used in South Australia weighs 17 oz., a schooner 10 oz., and a butcher 6 oz.
1979		Advertiser (Adelaide) 6 Apr. 3: The price of 170-millilitre (butcher) and 425-millilitre (pint) glasses [...] would increase by 1c.