A small tube of paper that's filled with tobacco and lit with a match is a cigarette. Because cigarettes take a terrible toll on smokers' health, the number of people who smoke them has declined recently.
Most cigarettes come in packages, each cigarette a perfect slim cylinder topped with a filter. When a cigarette is smoked all the way to this filter, it becomes a "butt." The main chemical in cigarettes is called nicotine, and it's extremely addictive — other additives in cigarettes can cause various cancers and lung diseases. Because of these dangers, cigarettes are regulated and highly taxed. The word itself comes from the French, meaning "little cigar."