Green’s Dictionary of Slang

one dram of spirits or the glass that holds it.

1824		J. Wight Mornings in Bow St. 85: [A]t length she consented to take a drop of something short — a cool dodger of cloves and brandy.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict.
1873		Sl. Dict.