vaporous

Vaporous is an adjective with several related senses. In its primary sense it describes something in a vapor state or pertaining to vapor, such as a substance that is gaseous rather than liquid or solid. It can also describe something that resembles vapor in appearance or quality—ethereal, misty, or insubstantial. In scientific and industrial contexts the term may refer to processes or materials involving vapor, including vapor deposition or vapor-phase reactions.

Etymology and spelling notes: the word derives from the noun vapor, with the adjectival ending -ous. In American English the standard spelling is vaporous; in British English the spelling vapourous is occasionally encountered, though much less common.

Usage and contexts: in physics and chemistry, vaporous describes substances that are in the vapor phase or atmospheres where vapor is present. In materials science, it is used to characterize coatings or layers formed by vapor deposition techniques such as chemical vapor deposition (CVD) or physical vapor deposition (PVD). In general writing, vaporous can convey a hazy, dreamlike, or intangible mood, as in descriptions of a vaporous atmosphere, a vaporous memory, or a vaporous fog enveloping a scene.