a reduction or concealment of night lighting in wartime to make the source less visible to an enemy from the air or sea.
a reduction of night lighting caused by a failure in an electric generating system or a reduction in its output.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use dim-out in a sentence
Along the shore no lights were showing for the dim-out was rigidly enforced at Sunset Beach.Voice from the Cave | Mildred A. Wirt