A piece of gold coin, value five shillings and three pence, frequently given to women of the town by such as professed always to give gold, and who before the introduction of those pieces always gave half a guinea.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Whore’s Bird * Whohe’s KitlingNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes