Running light

A running light was a source of illumination mounted on the exterior hull of a starship or other spaceship.

Running lights were situated on the rim of the primary hull of refit starships. There was one each on the dorsal and ventral surface, at port and starboard. 

In August of 2376, science officer Croth suggested using the USS Gryphon's running lights to tap out a message to the USS T'Kumbra, as his ship's communications array was damaged. 

In January of 2384, Commander Worf saw the runabout Roanoke's running lights through fog as it landed nearby.