The Collaborative International Dictionary of English v.0.48:

Parquet circle \Parquet circle\
   That part of the lower floor of a theater with seats at the
   rear of the parquet and beneath the galleries; -- called
   also, esp. in U. S., orchestra circle or parterre.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

parquet circle
    n 1: seating at the rear of the main floor (beneath the
         balconies) [syn: parquet circle, parterre]