Green’s Dictionary of Slang

1. the treadmill [= SE wheel].

1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.

2. a prison, i.e. the site of sense 1 [= Steel, the n. (2)].

1857

‘Ducange Anglicus’ Vulgar Tongue.

3. (US) a wheel.

1944

Maurer & Baker ‘“Aus.” Rhyming Argot’ in AS XIX:3.