Definition of "vapor" []

• Barely visible or cloudy diffused matter, such as mist, fumes, or smoke, suspended in the air. (noun)
• The state of a substance that exists below its critical temperature and that may be liquefied by application of sufficient pressure. (noun)
• The gaseous state of a substance that is liquid or solid under ordinary conditions. (noun)
• The vaporized form of a substance for use in industrial, military, or medical processes. (noun)
• A mixture of a vapor and air, as the explosive gasoline-air mixture burned in an internal-combustion engine. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "In visible light water vapor is not a problem; as long as clouds don't form, it's transparent."
• "Dryer B: A hot vapor is injected onto clothes inside the dryer drum."
• "Water vapor is the most powerful/ubiquitous greenhouse gas"