What term describes a system where no heat is exchanged with the surroundings?

The term that describes a system where no heat is exchanged with the surroundings is "adiabatic." In an adiabatic process, the system is insulated in such a way that heat cannot flow into or out of the system. This is significant in thermodynamics because it allows for the examination of energy transfer within the system solely in terms of work done.

In an adiabatic process, changes in internal energy are a result of work done on or by the system rather than heat transfer. This concept is crucial in various physical processes, such as the compression and expansion of gases, where the temperature of a gas can change due to work done on it, even if no heat enters or leaves the gas.

The other terms describe different types of conditions under which thermodynamic processes occur. Isothermal refers to processes at constant temperature, isobaric involves processes at constant pressure, and isochoric indicates processes at constant volume. None of these conditions specifically involve the absence of heat transfer, which is why they do not apply to the definition of an adiabatic process.