vocal cords

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

• noun plural Either of two pairs of bands or folds of mucous membrane in the throat that project into the larynx. The lower pair vibrate when air passing up from the lungs causes them to draw together, thereby producing vocal sounds. The upper, thicker pair are not involved in voice production.

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

• noun Two folds of tissue located in the larynx that vibrate when air passes over them, producing the sound waves associated with talking and singing.