nicotine

Definition of nicotine

nicotine

(NIH-kuh-TEEN)
An addictive, poisonous chemical found in tobacco. It can also be made in the laboratory. When it enters the body, nicotine causes an increased heart rate and use of oxygen by the heart, and a sense of well-being and relaxation. It is also used as an insecticide.

Source: NCI Dictionary of Cancer Terms