intrauterine device

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

• noun A birth control device, such as a plastic or metallic loop, ring, or spiral, that is inserted into the uterus to prevent implantation.

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

• noun A contraceptive device consisting of a small, usually plastic object placed within the uterus to prevent conception; also called IUD.

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

• noun A contraceptive device consisting of a spiral or similar shape of plastic or metal inserted through the vagina into the uterus in order to prevent the implantation of a fertilized egg.

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

• noun contraceptive device consisting of a piece of bent plastic or metal that is inserted through the vagina into the uterus