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.]

The Collaborative International Dictionary of English v.0.48:

Parterre \Par*terre"\, n. [F., fr. par on, by (L. per) + terre
   earth, ground, L. terra. See Terrace.]
   1. (Hort.) An ornamental and diversified arrangement of beds
      or plots, in which flowers are cultivated, with
      intervening spaces of gravel or turf for walking on.
      [1913 Webster]

   2. The pit of a theater; the parquet. [France]
      [1913 Webster]

WordNet (r) 3.0 (2006):

parterre
    n 1: an ornamental flower garden; beds and paths are arranged to
         form a pattern
    2: seating at the rear of the main floor (beneath the balconies)
       [syn: parquet circle, parterre]