Green’s Dictionary of Slang

1. (W.I.) one (old) penny; then three farthings.

1873		C. Rampini Letters from Jamaica 94: The negro nomenclature of coins is as follows: — Bill [sic: error for Gill], three farthings; Fip-pence, threepence; Bit, fourpence halfpenny; Joe, sixpence; Mac (macaroni), a shilling [DJE].
1879		De Montagnac 70: I buy a gill clay pipe [DJE].
1894		A. Spinner Study in Colour 83: I sell it for a gill an’ a quattie a-piece [DJE].
1905		J.G. Cruickshank Negro Humour 9: Dey will be glad of your half a bit an’ gill.
1912		C. McKay ‘Pay Day’ Constab Ballads 55: From a poun’ do’n to a gill.
1929		M. Beckwith Black Roadways 49: The following names [...] still in use today: Bit, 4½d. or 9 cents. Four bits, 1s. 6d. or 36 cents. Mac-and-thruppence, 1s. 3d. or 30 cents. Quattie, 1½d. or 3 cents. Gill, 3 farthings or 1½ cents.
1966		(ref. to 1940s) L. Bennett Jamaica Labrish 222: gill. three farthings.

2. (US) a coin.

1952

I, Mobster 108: I would put some gills in her hand and say that Vito had sent the money.