气团是在气象学中指温度和湿度在水平分布比较均匀的大范围的空气团。在地面天气图中，有高气压中心（H）与低气压中心（L）是很正常的，但是往往在某些特定的地方（例如：西伯利亚地区）会出现范围相当广大的高气压中心，其很明显地与一般小型的高气压系统有差异，因此对于这种出现在特定区域、大范围的高气压，给予「气团」（Air Mass）称呼，以别于一般小型的高气压系统。当然，气团遵循着北半球顺时针旋转、南半球逆时针旋转的气象学原理，但也因为是比较特殊的天气系统，因此对于气团，大多数的台湾中学教课书多提到气团的特征、气团的发源地、气团的变性等，而不会去提到当初对『气团』命名的理由。以至于许多学生，学到最后仍然会有「为什么气团都是高气压中心？」的疑惑。

In meteorology, an air mass is a volume of air defined by its temperature and water vapor content. Air masses cover many hundreds or thousands of square miles, and adapt to the characteristics of the surface below them. They are classified according to latitude and their continental or maritime source regions. Colder air masses are termed polar or arctic, while warmer air masses are deemed tropical. Continental and superior air masses are dry while maritime and monsoon air masses are moist. Weather fronts separate air masses with different density (temperature and/or moisture) characteristics. Once an air mass moves away from its source region, underlying vegetation and water bodies can quickly modify its character. Classification schemes tackle an air mass' characteristics, and well as modification.