E-cigarettes (e-cigs), vapes, vape or hookah pens, e-pipes, electronic nicotine delivery systems (ENDS), electronic smoking devices and other vaping products are battery-powered devices that allow users to inhale, or vape, aerosolized liquid (e-juice). E-cigarettes produce an aerosol by heating a liquid that usually contains nicotine - the addictive drug in regular cigarettes, cigars, and other tobacco products - flavorings, and other chemicals that help to make the aerosol. Users inhale this aerosol into their lungs. Bystanders can also breathe in this aerosol when the user exhales into the air. E-cigarettes can also be used to deliver marijuana and other drugs.
Source: IDPH Vaping Information