Green’s Dictionary of Slang

a small can, used to contain alcohol.

1674		‘Westminster Drollery’ in Ebsworth Choyce Drollery (1876) 192: O be drunk agen Quaker, / Take thy Canniken and shake her.
c.1698		B.E. Dict. Canting Crew n.p.: Cannikin, c. [...] a little Kan with a Spout to pour out the Wine or Beer, making it Froth.
1725		New Canting Dict.
1764		K. O’Hara Midas I v: And clink the cannikin here below.
1770		T. Chatterton Revenge I vi: Whilst thus I am drinking, [...] The cannikin clinking.
1785		Grose Classical Dict. of the Vulgar Tongue.
1846		D. Corcoran Picking from N.O. Picayune 102: And let me the canakin clink / [...] / Why then, let a soldier drink.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1879		London Life 21 June 6/1: And let me the canakin clink, clink; / And let me the canakin clink; / [...] / Why, then, let a soldier drink.