E-cigarettes also referred to as electronic cigarettes, mimic
smoking but don't really burn tobacco. In contrast, an electronic cigarette
uses battery power to burn heated liquid, creating an aerosol that is inhaled
into the lungs. Using an electronic cigarette is referred to as
"vaping".
E-juice also referred to as vape juice or liquid for electronic cigarettes, is what powers them.
Besides water and other ingredients, e-liquids may also contain
propylene glycol, vegetable glycerin, or glycerol (such as those used to make
flavors).