1. An electrical contact made between two circuits that are separated by a physical wall in such a way that the through connection does not make electrical contact with the wall.

2. A contact on a printed circuit board that connects one layer of interconnections with the next layer, passing through the insulating material that separates them. Up to 12 layers of interconnections have been mounted on a single board, although only a double-sided board is commonly used. In an integrated circuit containing multilayer interconnections, feedthroughs can be used to make contact between one layer of interconnections and the next.