“Quartern” is an obsolete term for a quarter of anything (228). In the context, the prince seems to be alluding to coins but is in reality speaking of the baroness, Julia, and Lisa as though they were two big loaves of bread and a bun thrown in for good measure (147, 251, 273). Rees (251) and Stedman (273) note that one can still buy quartern loaves (four-pounders!) in England.

Two half-quarterns and a make-weight
Act II