Green’s Dictionary of Slang

Yank mag n.

[play on Yank n. (2)/yank v.1 (5) + mag n.4 (1)]

American pulp magazines, as distributed in the UK.

[UK](con. 1960s) A. Frewin London Blues 98: He’s opened this shop selling Yank mags and pin-up mags and he wants some pictures for ‘out back.’.