Thermal openings are areas of the atmosphere that allow air to move freely between two different regions. The two most common types of thermal openings are exo and iso. Exo stands for exothermic, which is a process that releases energy in the form of heat. Iso stands for isothermal, which is a process that maintains a constant temperature. Thermal openings are important for regulating the temperature of the atmosphere and allowing air to move between different regions.