Green’s Dictionary of Slang

the vagina.

c.1386		Chaucer Wife of Bath’s Prologue line 607: And trewely, as myne housbondes tolde me, I hadde the beste quonyam myghte be.
1609		J. Hall Discovery of a New World (trans. Healey) 68 : A Quoniam is a glass as well knowne in Drinke-allia as Chaucers old Queynt is in Letcheri-tania.
1706		Hamilton ‘Scots Answer’ in Lord Poems on Affairs of State (1975) VII 225: While Virtuous Quondam Is Treated in Jest.