Green’s Dictionary of Slang

a prostitute who works in a brothel rather than walking the streets.

1606		A Choice, Chance and Change 70: His dainty Parnell hath no paragon.
1620		ballad in Chappell Roxburghe Ballads (1871) I 58: And pretty Parell [sic] shewes her legs, / As slender as my waste.
1678		E. Phillips New World Words (4th edn) n.p.: Parnel [...] an Appellation, particularly applied to any kind of wanton Woman.
1794		Caledonian Mercury 1 May 3/4: Ann Drew was accused of theft, perpetrated by house-breaking [...] The pannel [sic] was sentenced to be put in the pillory.
1890–1904		Farmer & Henley Sl. and Its Analogues V 133/1: Panel (Parnel or Pernel), subs. (old) An immodest woman; a prostitute.