Which term indicates that entropy remains constant in a process?

The term that indicates that entropy remains constant during a process is isentropic. In thermodynamics, isentropic processes are characterized by being both adiabatic (no heat transfer) and reversible, which means the entropy does not change throughout the process. This is significant in many engineering applications, particularly in the analysis of thermodynamic cycles, such as those found in turbines and compressors, where one aims to achieve maximum efficiency by minimizing entropy generation.

The concept of an isentropic process helps establish ideal performance benchmarks for real systems by providing a reference state that can be compared against actual processes, which often involve entropy generation due to irreversibilities and heat transfer. Understanding isentropic processes is crucial for engineers in the design and analysis of energy systems and machinery.

The other terms relate to specific characteristics of thermodynamic processes but do not imply constant entropy. An adiabatic process focuses on the absence of heat transfer, isochoric refers to processes at constant volume, and isobaric involves constant pressure. None of these terms, by themselves, signify that the entropy remains unchanged throughout the process.