Green’s Dictionary of Slang

1. a bookmaker.

1894		Truth (Sydney) 14 Jan. 1/6: Some of the tiny ‘Tommies,’ or outside bookies, are evidently men of thrift.
1897		W.A. Sun. Times (Perth) 19 Dec. 5/1: Even 1,000 to 1 is not a fair price [...] especially as the ‘Tommy’ is sure to get away well.
1903		Sun. Times (Perth) 9 Aug. 4/8: He has joined the swarm of Tommy Rookes / Who’ve gone to grab the dross.
1904		Sun. Times (Perth) 31 Jan. 1/1: In addition to doing all his ducats another Tommy was jostled for all his jewellery.
1909		Sun. Times (Perth) 28 Feb. 4s/7: The Tommy Rooks, with Jewish jibs, / Chew chicken at the Strand.
1915		Drew & Evans Grafter (1922) 1: The Grafter worked as only an outer Tommy can work.
1927		C. Drew ‘Grafter and Goose’ in Bulletin (Sydney) 11 Aug. n.p.: Some two hundred ‘Tommies’ with betting-bags slung across their shoulders were working for dear life to find a favorite.
1937		Sydney Sportsman (Surry Hills, NSW) 22 Sept. 6/1: Among the Yaralla bets that found a resting place in the tommies’ satchels were £600 to £200 Eric Welch.
1943		Baker Popular Dict. Aus. Sl. (2nd edn).

2. a bookmaker’s ledger.

1934		Age (Melbourne) 12 Sept. 8/7: In Brennan’s possession was a book known as a ‘tommy,’ which was a form of sweep.
1953		Baker Aus. Speaks.