The Collaborative International Dictionary of English v.0.48:

Folding \Fold"ing\, n.
   1. The act of making a fold or folds; also, a fold; a
      doubling; a plication.
      [1913 Webster]

            The lower foldings of the vest.       --Addison.
      [1913 Webster]

   2. (Agric.) The keepig of sheep in inclosures on arable land,
      etc.
      [1913 Webster]

   Folding boat, a portable boat made by stretching canvas,
      etc., over jointed framework, used in campaigning, and by
      tourists, etc. --Ham. Nav. Encyc.
      [1913 Webster]

   Folding chair, a chair which may be shut up compactly for
      carriage or stowage; a camp chair.

   Folding door, one of two or more doors filling a single and
      hung upon hinges.
      [1913 Webster]

WordNet (r) 3.0 (2006):

folding door
    n 1: an interior door that opens by folding back in sections
         (rather than by swinging on hinges) [syn: folding door,
         accordion door]