English

Blue light, a pyrotechnic signal.

Blue light on a police vehicle.

Noun

blue light ‎(countable and uncountable, plural blue lights)

1. (historical, uncountable) A mixture of chemicals (including nitre, sulphur and antimony) used in eighteenth and nineteenth centuries for pyrotechnics, night-time signaling and general illumination.
   • 1828, Gray, Samuel Frederick, The Operative Chemist, page 499:

     Blue lights, or blue fire, is a preparation in which zinc and sulphur, or sulphur alone, are used. The particular colour is communicated by the zinc and sulphur.

   • 2015, Ragan, Mark K., quoting Robert Fleming, Proceedings of a Naval Court of Inquiry into the Sinking of the Housatonic, 1864, quoted in Confederate Saboteurs, Texas A&M University Press, ISBN 9781623492786, page 98:

     When the 'Canandaigua' got astern, and was lying athwart, of the 'Housatonic,' about four ship lengths off, while I was in the fore rigging, I saw a blue light on the water just ahead of the 'Canandaigua,' and on the starboard quarter of the 'Housatonic.'

2. (countable) A flashing light, usually fitted to an emergency vehicle.

Usage notes

The original chemical mixtures burned with a blue flame. Later versions omitted any colouring agents, producing a bright white light, but retained the name by convention.

Synonyms

• (chemicals): Bengal fire, Bengal light
• (flashing lights): cherry light, lightbar

Translations

Verb

blue light ‎(third-person singular simple present blue lights, present participle blue lighting, simple past and past participle blue lighted)

1. (law enforcement) To travel quickly in a police vehicle with the lightbar (and possibly the siren) activated.
   • 2011, Donoghue, John, Police, Crime & 999, Troubador Publishing, ISBN 9781848768840:

     When we weren't blue lighting, we had to obey the 30 mph limit, but out of town we had a training exemption from any speed regulations and were encouraged to push the car to its limits... and we did.

   • 2012, Mukand, Jon, The Man with the Bionic Brain, Chicago Review Press, ISBN 9781613740583:

     They jumped into his cruiser and blue-lighted it to Boston Medical Center at eighty miles per hour.

   • 2014, Rennie, James, The Operators, Pen and Sword, ISBN 9781473834965:

     Roger that. Feds and green army are blue lighting to you.

Hypernyms

• See Wikisaurus:move quickly

References

• “blue light” (US) / “blue light” (UK) in Oxford Dictionaries, Oxford University Press.