The following definitions are the commonly accepted terminology associated with the futon furniture and sofa-bed industry.
Decks:
Decks are the platforms on which the futon rests for both convertible futon sofa-bed frames and stationary platform beds.
Seat Deck:
The seat deck is the deck on which the user sits when a futon sofa-bed is in the sitting position.
Back Deck:
The back deck is the deck which the user leans back on when a futon sofa-bed is in the sitting position.
Tri-fold:
A convertible futon sofa-bed frame that utilizes three decks. The futon mattress can hang over the back of the frame, be folded under itself on the seat deck, or lay flat as a chaise lounge style seat. The tri-fold allows the futon mattress to fold twice along its usually shorter width.
Bi-fold:
A convertible futon sofa-bed frame that utilizes two decks. The bi-fold allows the futon mattress to fold once along its length.
Kicker:
The kicker is usually a small piece of wood or plastic that wedges itself between the seat deck and the back deck so the frame can be returned from a sleeper to a sofa in a simple, fluid motion. Several industry patents have been granted for the kicker.
Wall-Hugger:
A wall-hugger is a frame that can open to a sofa-bed without moving the base of the frame away from the wall. We categorize wall-huggers by their tolerance. A zero tolerance wall-hugger can be placed directly against the wall and still not touch the wall when converting. Other wall-huggers must be placed a short distance from the wall. These are called two, three, four etc. inch tolerance wall-huggers. Be sure to ask your manufacturer about the tolerance of their wall-hugger.