Humidifier 2 topics · 2 sources Healthcare› MedicineCancer(hyoo-MID-ih-fye-er) A machine that puts moisture in the air.National Cancer Institute — Dictionary of Cancer Terms Cite ScienceEnergyA device used to maintain a specified humidity in a conditioned space.US DOE Office of Energy Efficiency & Renewable Energy — Glossary of Energy-Related Terms retrieved 2014-05-26 Cite