The definition of a measure air flow is the process of measuring the amount of air that is moving through a space. This can be done in a variety of ways, such as using a fan to measure the speed of the air, or using a flow meter to measure the volume of air that is passing through a space. Measuring air flow is important for a variety of reasons, such as ensuring that the air quality in a space is adequate, or that the air is moving in the right direction for the desired effect. It can also be used to determine the efficiency of a ventilation system, or to ensure that the air is being circulated properly. In addition, measuring air flow can be used to identify potential problems in a space, such as leaks or blockages, and to ensure that the air is being distributed evenly throughout the space. Ultimately, measuring air flow is an important part of maintaining a healthy and comfortable environment.