ligation

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

• noun The act of binding or of applying a ligature.
• noun The state of being bound.
• noun Something that binds; a ligature.

from The Century Dictionary.

• noun A tying or binding, or the state of being tied or bound; constriction by a ligature or bond; especially, in surgery, the operation of tying an artery to prevent hemorrhage, as after amputation, etc.

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

• noun The act of binding, or the state of being bound.
• noun That which binds; bond; connection.

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

• noun Something that ties, a ligature.
• noun The act of tying, of applying a ligature.
• noun The state of having a ligature, of being tied.
• noun medicine The act of tying off or sealing a blood vessel or fallopian tube during surgery.

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

• noun (surgery) tying a duct or blood vessel with a ligature (as to prevent bleeding during surgery)