A lighthouse is a structure such as a tower or a building designed to emit light from a system of lamps and lenses. It is used as a navigational aid for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs or safe entries to harbors.
AtoN (Aid to Navigation) is any sort of marker which aids the traveller in navigation; the term is commonly used to refer to nautical travel. Common types of such aids include buoys, fog signals and day beacons.
According to the "Light list glossary of terms" of the United States Coast Guard, an Aid to Navigation is any device, external to a vessel, specifically intended to assist navigators in determining their position or safe course, or to warn them of dangers or obstructions to navigation – under this perspective lighthouses are also considered AtoNs.
In MarineTraffic, the term Lights is used to describe all the above-mentioned navigation aids. Lights can be displayed on the MarineTraffic Live Map with their distinctive icon for easier identification. All you have to do is to tick the selection box next to the Lights and AtoN option at the Layers section of the Live Map Toolbar.