Definitions
1.NounA mixture of chemicals (including nitre, sulfur and antimony) used in the eighteenth and nineteenth centuries for night-time signaling and general illumination. .mw-parser-output .defdate{font-size:smaller}
2.NounA New England federalist, who opposed the Anglo-American War of 1812; , a federalist.
3.NounA flashing light, usually fitted to an emergency vehicle.
4.NounUsed other than figuratively or idiomatically: see blue, light.
5.VerbTo travel quickly in a police or ambulance vehicle with the lightbar (and possibly the siren) activated.