A technical term for the work done pushing out the atmosphere by a system that changes its volume.

A car engine's pistons, for example, have to push out the atmosphere - in effect lifting a column of atmosphere the same diameter as the piston vertically through a height equal to the stroke of the piston - every time they move out. This amount of useless work would equal P_atmos x Swept Volume if the process was quasistatic but, since the process is not, must be greater than this.