Pseudo Stirling cycle
The pseudo Stirling cycle, also known as the adiabatic Stirling cycle, is a thermodynamic cycle with an adiabatic working volume and isothermal heater and cooler, in contrast to the ideal Stirling cycle with an isothermal working space. The working fluid has no bearing on the maximum thermal efficiencies of the pseudo Stirling cycle.
Practical Stirling engines usually use a adiabatic Stirling cycle as the ideal Stirling cycle can not be practically implemented.
Nomenclature and lack in specificity can cause confusion.