Vaporization
 of an element or compound is a phase transition from the liquid phase 
to gas phase. There are two sorts of vaporization: evaporation and 
boiling. 
 
Evaporation is a phase transition from the liquid phase to gas phase that occurs at temperatures below the boiling temperature at a given pressure.
 
Boiling is a phase transition from the liquid phase to gas phase that occurs at or above the temperature the boiling temperature.
Evaporation is a phase transition from the liquid phase to gas phase that occurs at temperatures below the boiling temperature at a given pressure.
Boiling is a phase transition from the liquid phase to gas phase that occurs at or above the temperature the boiling temperature.