Diameter. The greatest distance across a flat canopy, from skirt to skirt, measured when the canopy is lying flat. This measurement designates the size of the parachute in feet.

Diaper. Generally, a fabric panel secured by the suspension lines, which is sewn to and wrapped around the canopy. Used to control and reduce opening forces. Found mostly on round reserves.

Die. The lower part of the tool used in a press to install snap fasteners or grommets.

Direct bag static line system. A static line deployment system where the bag is attached to the static line and the canopy deploys free into the airstream.

Double throw zigzag stitching. Stitching in which the needle makes a center stitch between each left and right stitch. Also known as a No. 308 stitch.

Double-W. A three-point cross-stitch.

Drop test. Dropping a dummy or other load from an aircraft in flight or otherwise simulating a live jump to prove serviceability of a parachute.

Drop zone (DZ). A specified area upon which personnel or equipment are dropped by parachute.

Drying tower. A facility where parachutes are suspended for airing and drying.

Dual parachute packs. A sport assembly consisting of a main and a reserve parachute.

Dummy (parachute). Torso-shaped dummy of variable weight used for testing parachutes; may be of fixed or articulated construction.

Dummy drop. A parachute test using a dummy as the suspended load.

Durable dot fastener. The common snap fastener used for closing flaps, etc.

Ejector type snap harness. A harness snap that attaches to the V-ring to secure two parts of the harness together. An ejector arm expels the V-ring when the finger-grip lever is pulled outward.

Emergency parachute. A certificated parachute intended for emergency use.

End flap. The fabric on the end of a pack as opposed to the side, used to enclose and protect the canopy.

End tabs. Metal tabs on the end flap of the pack (principally chest and seat containers) used to secure it closed.

Eye. A small steel-wire loop attached to the parachute pack into which a hook on a pack-opening elastic is fastened.