Parachute cord (also paracord or 550 cord when referring to type-III paracord) is a lightweight nylon kernmantle rope originally used in the suspension lines of parachutes. This cord is now used as a general-purpose utility cord. This versatile cord was used by astronauts during the 82nd Space Shuttle mission to repair the Hubble Space Telescope.
The braided sheath is usually made up of 32 interwoven strands, giving it a relatively smooth texture. The all-nylon construction makes paracord somewhat elastic.
Current technical standards for the manufacture of cord for use in parachutes are published by the Parachute Industry Association. The now inactivated US military standard MIL-C-5040H required the material to be nylon. Similar styles of the cord are manufactured with other materials such as polyester.
The yarns of the core (commonly referred to as "the guts") can also be removed when finer string is needed, for instance as sewing thread to repair gear, or to be used as fishing line in a survival situation. For applications requiring a thinner or less elastic cord, such as shoelaces, users often remove the yarn in the core and use the nylon sheath alone. The ends of the cord can be melted and/or crimped to prevent fraying.
There are also modern versions of parachute cord that include non-traditional survival strands within the core such as fishing line, fire tinder, and even snare wire. Paracord has also been used for whipmaking. The durability and versatility of this material have proved beneficial for performing whip crackers and enthusiasts. Since nylon does not rot or mildew, it has become known as an all-weather material for whipmaking.