Which term describes the boundary between two different air masses?

The term that describes the boundary between two different air masses is a "Front." In meteorology, fronts are significant because they indicate a transition zone where the characteristics of air masses change. Different air masses can have varying temperatures, humidity levels, and overall properties, and the front is the area where these differences meet.

When a front forms, it can lead to various weather phenomena, including precipitation, changes in temperature, and shifts in wind patterns. For instance, a cold front occurs when a cooler air mass moves into an area occupied by warmer air, resulting in uplifting of the warmer air, which can cause clouds and storms. A warm front, conversely, happens when warm air moves over a cooler air mass, usually resulting in gentle rain or overcast conditions.

Other terms like pressure system, weather front, and depression refer to different meteorological concepts. While "weather front" is commonly used, it is essentially a synonym for "front." "Pressure system" pertains to regions of high or low atmospheric pressure, which can influence weather but does not directly describe the boundary itself. "Depression" refers to a low-pressure area that can be associated with fronts but does not specifically denote the boundary between differing air masses. Thus, "Front" is