atrioventricular node

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

• noun A small mass of specialized cardiac muscle fibers, located in the wall of the right atrium of the heart, that receives electrical impulses from the sinoatrial node and directs them to the conduction system in the walls of the ventricles.

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

• noun a node of specialized heart muscle located in the septal wall of the right atrium; receives impulses from the sinoatrial node and transmits them to atrioventricular bundle