A Cigarette Lighter is an implement used to light
cigarettes, normally containing
flammable gas and some kind of
ignition system to light said gas at the correct moment.
Annoyingly, this is an implement commonly forgotten by Cigarette Smokers in pubs and bars. This leads to the phrase "Excuse me, do you have a light?" interrupting your conversations at regular intervals as someone waves a cigarette in front of their mouths a la Groucho Marx with his cigar and looks at you expectantly.
For gods sakes people, if you're going to smoke bring a bloody lighter.