Definition of "nicotine" []

• A colorless, poisonous alkaloid, C10H14N2, derived from the tobacco plant and used as an insecticide. It is the substance in tobacco to which smokers can become addicted. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The vast majority of smokers start in childhood and then find it very difficult to quit because nicotine is addictive."
• "They weren't based on hard science connecting health hazards to long-term nicotine addiction, but were set to mirror the length of use in clinical trials."
• "I've heard it said that nicotine is more addictive than any other drug, including heroin."