A bar mounted on the roof of a vehicle, such as a police car, with rotating beacons or other lights to provide a visual warning.(noun)
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Use "lightbar" in a sentence
"The nose design is taken directly from the Aero-X concept car and the production 9-5 will be marked out by a distinctive 'lightbar' running across the rear of the car, between the rear light clusters."
"It kinda looks like the ugly cousin of the lightbar from the Kitt Knight Rider car."
"Externally, it would have a yellow lightbar or strobe, a search light, vehicle ID numbers, a 'If this driver is operating...' sticker, commercial plates, a ladder rack, several antenna, a innocuous company name with a cruddy logo."