flap seat

Noun

flap seat (plural flap seats)

1. A hinged seat that can be raised when not in use.
   • And be it enacted that […] no person […] presume to wish to go out for ginger-beer or oysters between the acts, to the annoyance of the nine rows of audience behind him, and the especial discomfiture of the fat old gentleman with the child on his knees, who sits on the flap-seat by the box-door.1843, Albert Richard Smith, “The Bureau Drawer”, in The Wassail-Bowl, volume 1, London: Richard Bentley, pages 115–116
   • Entering the vast edifice, capable of seating many thousands of people, you are directed, if a stranger, to sit on a flap-seat attached to the end of the regular pews in the aisle until the owners or usual occupants are all seated, and then shown to your place.1889, George H. Luce, chapter 3, in Our Pilgrimage, Milwaukee: Young Churchman, page 93

   Synonyms:

   folding seat, tip-up seat

2. A flap on the part of an undergarment or night garment that covers the buttocks.
   • After several minutes, Liebknecht stood barefoot in a suit of long winter underwear. Some of its buttons were missing and the flap seat was baggy from too much laundering.1954, Ben Hecht, A Child of the Century, New York: Simon and Schuster, Book 4, p. 273
   • They wrapped themselves up to their eyes in thick sweaters, heavy shirts, wool socks and long union suits with flap seats.1970, Winston M. Estes, chapter 9, in Another Part of the House,, New York: Avon, published 1978, page 129