Also found in: Dictionary.
To darken completely after a period of dimming. We were all disappointed when the lights dimmed out in the middle of our party.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
[for a light] to grow dim and go out altogether. The lights dimmed out twice during the storm. I was afraid that the lights would dim out completely.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.