a : change from a liquid to a vapor //evaporation of water //But warming increases the evaporation of ocean water, which could increase the snowfall on the Arctic and Antarctic ice sheets, remove water from the ocean, and lower sea level. — Jack M. Hollander
b : the vanishing or disappearance of something //The pope's attempt to arrest the evaporation of the Christian tradition in Europe was also unsuccessful. — Conrad Black //No longer a machine that accelerates the evaporation of resources, in the Roman context the banquet becomes a theatre of wealth and property, of social distinction, or social-climbing. — James N. Davidson