A person begotten on a black woman by a white man. One of the blue squadron; any one having a cross of the black breed, or, as it is termed, a lick of the tar brush.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Blue Plumb * Blue TapeNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes