1. (circa 1960) A device that uses eddy correlation to measure the turbulent vertical flux density of water vapor within a few meters of the surface of the earth. Evapotrons were originally designed with analog electronics to make the necessary covariance calculations in real time. This term is not in common use for systems that make the covariance calculations with modern digital electronics.

2. (circa 2010) A device employed in ecologically sensitive arid environments to dispose of contaminated water by evaporation. Such devices were invented in response to the "Leave No Trace" obligation for camps at the Burning Man art festival to dispose of wastewater responsibly. The predominant designs are the "Gray-B-Gon", which is wind-powered, and the "Pumped Cascade", which is powered by an electricity source driving a small pump. See www.evapotrons.info for evapotron history, design varieties, and construction guidance.