Madam Van, n. — Green’s Dictionary of Slang

Madam Van n.

also Madame Rhan, Madam Ran

[? a real-life whore or madam or (given the contemporary role of the Dutch as ‘national enemy’) f. the common van pfx used in Du. surnames; Grose, 1785, 1796, Madam Ran, are misprints]

(UK Und.) a prostitute.

c.1698		B.E. Dict. Canting Crew n.p.: Madam Van, c. a Whore, ‘The Cull has been with Madam Van ... the Fellow has enjoyed such a one.’.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Madam ran, a whore (cant).
1811		Lex. Balatronicum [as cit. 1785].
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue [as cit. 1785].
1859		‘Scene in a London Flash-Panny’ Matsell Vocabulum 100: ‘Well said,‘Madame Rhan, ‘but the bishop might as soon call the parson pig-stealer.’.