back flap, back fold, back shutter

The leaf in a window shutter that folds behind the exposed leaf of the shutter; that part of a window shutter that folds into a recess in the window casing.

backflap hinge, flap hinge

A hinge having a flat plate or strap which is screwed to the face of a shutter or door.

McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.