Evaporation takes place when liquid turns into gas. Ever noticed how water disappears from a glass if you leave it sitting on your counter? That's not thirsty gnomes living in your kitchen: it’s evaporation.
Evaporation comes from the Latin evaporare, which means “disperse in vapor or steam.” Depending on the humidity level of the air around it, any liquid will release some of its molecules into the atmosphere around it. That’s evaporation. With time, the liquid can fully evaporate. That's why evaporation can apply to anything that disappears, like the evaporation of your money that leaves you with nothing but an empty wallet.