Green’s Dictionary of Slang

1. a quart pot or a quart of liquor.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict. 225: ‘shant of bivvy,’ a quart of beer.
1873		N.S. Dodge ‘Vagrants and Vagrancy’ in Appleton’s Journal (N.Y.) 6 Sept. 308/1: The cant phrase, shant of gatter (pot of beer), seems never to have come over the water.
1881		Newcastle Courant 2 Dec. 6/6: Here’s a boozing ken, we’ll have a shant or two of bivvy.
1893		P.H. Emerson Signor Lippo 13: I should just think you would beg my pardon and to show you mean it stand a couple of shants of bevarly to square the boys.
1895		C. Crowe Aus. Sl. Dict. 72: Shant of Bivvy, a quart of beer.

2. a drink, esp. beer; spec. a pint, see quote 1888.

1856		H. Mayhew Great World of London I 6: Will you have a shant o’ gatter (pot of beer) after all this dowry of parny (lot of rain)?
1865		Leaves from Diary of Celebrated Burglar 51/2: The arrival of a fresh face was the signal for another ‘shant,’ and forward we marched to the bar.
1882		Sydney Sl. Dict. (2 edn) 4: ‘[S]hant o’ gatter,’ pot o’ beer.
1888		S.O. Addy Sheffield Gloss. 207: Shant, a pint. ‘A shant of booze’ is, I am told, a pint of beer.
1893		P.H. Emerson Signor Lippo 47: Then we went out for a shanty.
1900		Eve. Teleg. (Dundee) 1 Sept. 3/6: The language of the London East-end pub [...] ‘Shant o’ bivvy,’ and ‘Shant-o’-gatter’ — glass of ale.
1909		J. Ware Passing Eng. of the Victorian Era 220/2: Shant of bivvy (Hatton Garden). Pint of beer.
1965		L. Dunne Goodbye to The Hill (1966) 63: He fancied a good shant.
1977		D. Powis Signs of Crime 200: Shant A drink, principally an alcoholic drink.
1979		(con. 1920s) J. White ‘Campbell Bunk’ in History Workshop 26: A rich vein of slang which harked back to an older london street culture [...] Words which were not current in ordinary working-class speech [...] shant (glass of beer) .
1989		(con. 1950s–60s) in G. Tremlett Little Legs 151: We’re all just sitting there [...] me just having a shant.
2007		N. ‘Razor’ Smith Raiders 67: I didn’t mind driving, even though I’d had a few shants.
2011		J.J. Connolly Viva La Madness 27: I just wanna get it done, have a shant. Go off duty.

3. beer money.

1893

P.H. Emerson Signor Lippo 11: Any shanty in your sky-rocket?