Green’s Dictionary of Slang

an inside pocket.

1812		Vaux Vocab. of the Flash Lang.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1834		(con. 1737–9) W.H. Ainsworth Rookwood (1857) 178: No slour’d hoxter my snipes could stay.
1859, 1860		Hotten Dict. of Modern Sl. etc.
c.1870		ballad in Farmer Musa Pedstris (1896) Appendix 250: All for bashin’ a bloke down our a-alley, / And a’ takin’ his huxters away!
1873		Sl. Dict.