This is not considered smoke because it is only vapor, to inhale vapor through the mouth from a usually battery-operated electronic device (such as an electronic cigarette) that heats up and vaporizes a liquid , This electronic cigarette … contains a small reservoir of liquid nicotine solution that is vaporized to form an aerosol mist.
The user “vapes,” or puffs on the vapor, to get a hit of the addictive nicotine and flavoring.