As defined by the Cleveland Clinic, "Vaping is the act of inhaling and exhaling an aerosol produced by a battery-powered device, commonly known as an e-cigarette or vape. These devices heat a liquid (e-liquid or vape juice) into a mist, which is inhaled directly into the lungs"

Nicotine is a naturally occurring psychoactive stimulant found in a variety of plants; the most common of which is Tobacco.  

Fun Fact:  Nicotine is also found to a lesser extent in "night shade vegetables" (tomatoes, potatoes, eggplants, and green peppers) as well as some other vegetation.  (info taken from Science Daily) 

Vape devices vary widely in appearance. Some look like traditional cigarettes or writing pens, while others resemble USB flash drives or brightly colored, sleek gadgets. 

Because the aerosol contains harmful chemicals and highly concentrated nicotine, public health organizations generally warn that it is not a safe alternative to smoking and poses various health and addiction risks