vaporium
A curved hollow metal sheet that is filled with boiling water and used for the therapeutic application of heat.
Dr. Felix Bricheteau, in the Bull. Gen. de Therup. for July, 1867 recommends the " vaporium," or chamber filled with the vapor of water in pulmonary consumption.
A steam bath (room for taking steam baths).
The flues for conveying the warm water into the sweating room, and the fireplace, were also found in a pretty perfect state, as well as a tesselated floor laid over hollow bricks planted round the circular vaporium.
A shop where one can buy e-cigarettes and vaping paraphernalia, sometimes with a lounge for smoking them.
Retail vaporiums sell flavored vapor cartridges -- with or without nicotine.
Where it comes from
From vape + -orium or vapor + -ium, or in sense 3, possibly a blend of vape + emporium.
Adapted from the Wiktionary entry vaporium (CC BY-SA 4.0).