Green’s Dictionary of Slang

block n.5

1. [1910s+] (Aus./US Und.) a watch; thus block-dealer, a watch seller, a jeweler [block and tackle n.1 ].

2. [1970s] (Can. prison) a cigarette lighter [resemblance].

In compounds

block and slang (n.) [slang n.2 (2)]

[1910s–40s] (US Und.) a gold watch and chain.

block and tackle (n.)

see separate entry.