ligament

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

• noun Anatomy A sheet or band of tough, fibrous tissue connecting bones or cartilages at a joint or supporting an organ.
• noun A unifying or connecting tie or bond.

from The Century Dictionary.

• noun A connecting tie or band; anything that binds objects or their parts together; any bond of union, material or immaterial.
• noun Specifically— In anatomy, a band of connective tissue serving to bind one part to another.
• noun In conchology, a band of uncalcified chitinous cuticular substance which unites the valves of a bivalve shell.
• noun Of the uterus, the fold of peritoneum which extends from the uterus to the pelvis on either side.
• noun Of the liver, the impervious cord formed by the umbilical vein, passing from the navel to the under surface of the liver.
• noun Of the uterus, a rounded cord on each side between the layers of the broad ligament, passing from the upper part of the womb to the internal abdominal ring and thence through the inguinal canal to the labia majora, consisting of fibrous, areolar, and some muscular tissue, with vessels and nerves inclosed in a fold of peritoneum. It corresponds in part to the spermatic cord of the male.
• noun Of the mammæ, processes of the superficial thoracic fascia entering and supporting these glands.
• noun Of the penis, the fibrous attachment of the root of the organ to the symphysis pubis.
• noun Of the spleen, a fold of peritoneum connecting the spleen with the diaphragm.

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

• noun Anything that ties or unites one thing or part to another; a bandage; a bond.
• noun A tough band or plate of dense, fibrous, connective tissue or fibrocartilage serving to unite bones or form joints.
• noun A band of connective tissue, or a membranous fold, which supports or retains an organ in place.

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

• noun anatomy band of strong tissue that holds the bones of an animal in position

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

• noun any connection or unifying bond
• noun a sheet or band of tough fibrous tissue connecting bones or cartilages or supporting muscles or organs