bungee cord

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An elasticized rubber cord, often fitted with hooks at the ends, used to fasten, bear weight, or absorb shock.

from the GNU version of the Collaborative International Dictionary of English.

• noun a strong elastic cord, usually with a hook at each end, used as a shock-absorbing device or to bind packages together, as on a dolly or handcart.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A long elastic cord tied around the ankles of the jumper in bungee jumping.
• noun An elastic fabric-bound strap with a hook at each end, used for securing luggage.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an elasticized rope