Green’s Dictionary of Slang

1. (Aus./US Und.) a watch; thus block-dealer, a watch seller, a jeweler, red block, a gold watch, white block, a silver watch [block and tackle n.¹ ].

1910		Register (Adelaide) 4 Jan. 10/3: I’ll take a ‘leather’, but I won’t touch ‘reds‘ or a ‘block’.
1914		Jackson & Hellyer Vocab. Criminal Sl. 17: block [...] A watch. Example: ‘The wire rung six blocks in the breaks,’ i. e., ‘The tool (pickpocket) detached six watches from their rings in the crowded exit.’.
1924		G. Henderson Keys to Crookdom 397: Block. Solid-gold watch.
1922		Argus (Melbourne) 23 Mar. 6/7: If he has had a successful day the other ‘dip’ would reply in these terms, ‘I got two ‘presents,’ a ‘pogue,’ a red ‘block,’ two white ‘blocks,’ [...] Translated, this means, ‘I obtained two sums of money from men’s hip-pocket, a wallet containing, a considerable sum of money, a gold watch, two silver watches [...]’ .
1926		‘Und. and Its Vernacular’ in Clues mag. 158–62: block-dealer Watch-dealer; jeweler.
1931		Irwin Amer. Tramp and Und. Sl.
1933		‘Goat’ Laven Rough Stuff 39: He told us of different houses throughout the country that dealt in brass peddling, such as blocks, which is what watches are called in the West. In the East they call ’em soupers, and in England, kettles.
1933		Ersine Und. and Prison Sl. 19: block, n. 1. a cheap watch.
1936		(ref. to 1920s) L. Duncan Over the Wall 112: Then the junk – small rocks, hoops and blocks – ticking rhythmically.
1950		Goldin et al. DAUL 29/2: Block. A genuine gold-cased watch as differentiated from thin-plated watches.
1962		Ragen & Finston World’s Toughest Prison 791: block – A watch.
1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xxxii 6/1: block: A dud watch. They looked like gold but would turn the wrist green after a very short while.
1975		Bulletin (Sydney) 26 Apr. 44: ‘What was you duddin’? The Ampol buildin’ or somethin ?’ ‘Blocks. Just bottom shelf stuff with face lifts for the mugs.’.
1983		R. Aven-Bray Ridgey-Didge Oz Jack Lang 21: Block Dud watch.
2001		D. Looser Boobslang [U. Canterbury D.Phil. thesis] 20/2: block 2 a wristwatch.

2. (Can. prison) a cigarette lighter [resemblance].

1978

R. Caron Go-Boy! 23: OK, boys, Mother Goose sent me over to collect your blocks for refuelling.

3. (N.Z. prison) a firearm.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 20/2: block 4 a firearm.