Which term is synonymous with the weight of air in a specific volume?

The term that is synonymous with the weight of air in a specific volume is atmospheric pressure. Atmospheric pressure is defined as the force exerted by the weight of air above a given point, measured per unit area. At sea level, this pressure is approximately 101.3 kPa (kilopascals) and represents the weight of the column of air above that point. As air has mass, it exerts a force due to gravity, leading to pressure measurements that quantify this weight in terms of force per area.

While density refers to the mass of air per unit volume, atmospheric pressure directly relates to the weight exerted by that mass over a particular area, making atmospheric pressure the correct term in this context. It is also important to note that draught typically relates to airflow and ventilation refers to the movement of air, neither of which captures the concept of weight in a specific volume as effectively as atmospheric pressure does.