catgut

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

• noun A tough thin cord made from the treated and stretched intestines of certain animals, especially sheep, and used for stringing musical instruments and tennis rackets and for surgical ligatures.

from The Century Dictionary.

• noun catgut impregnated with chromic acid, in consequence of which it is less quickly absorbed when used for sutures or ligatures in surgical operations.
• noun The intestines of sheep (sometimes of the horse, the ass, or the mule), dried and twisted, used for strings of musical instruments and for other purposes; a string of this kind.
• noun A sort of linen or canvas with wide interstices.
• noun A name for one of the olive seaweeds, Chorda filum, which is allied to Laminaria. The plant Tephrosia Virginiana: so called on account of its long, slender, and very tough roots.

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

• noun A cord of great toughness made from the intestines of animals, esp. of sheep, used for strings of musical instruments, etc.
• noun A sort of linen or canvas, with wide interstices.

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

• noun countable A cord of great toughness made from the intestines of animals, especially of sheep, used for strings of musical instruments, etc.
• noun uncountable The material from which such cords are made.
• noun uncountable A sort of linen or canvas, with wide interstices.

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

• noun a strong cord made from the intestines of sheep and used in surgery
• noun perennial subshrub of eastern North America having downy leaves yellowish and rose flowers and; source of rotenone