An adiabatic process is a thermodynamic process, there is no gain or loss of heat.

entropy of thermodynamic systems

specific heat

An isoentropic process is a chemical or thermodynamic process in which entropy does not change. An example a reversible adiabatic process is isoentropic.

At engineering level technically both process are same except there definition both process give hyperbolic curve in P-V diagram and straight line in T-S diagram. and even in polytropic process PV^n=constant if n=1 then it is not hyperbolic process it is isothermal process even though the definition says pv=c is hyperbolic process.