Green’s Dictionary of Slang

1. (US) a pair of outsize boots or shoes [SE tannery, a leather-maker’s].

1909

(ref. to 1880) J. Ware Passing Eng. of the Victorian Era.

2. (Aus.) a school [errant pupils will receive a tanning n.].

1912

Bulletin (Sydney) 26 Dec. 13/4: I have taught school in most parts of Victoria (by the way, the technical term for teaching is ‘running a tannery’), and it has been interesting to study the effect environment has on nippers.