A thermistor is a component that:

A thermistor is a type of resistor whose resistance varies significantly with temperature. This characteristic makes thermistors very useful in temperature sensing applications. They are made of semiconductor materials, and their resistance can either increase or decrease with changes in temperature, depending on the type of thermistor.

For instance, negative temperature coefficient (NTC) thermistors decrease in resistance as temperature increases, while positive temperature coefficient (PTC) thermistors increase in resistance as temperature rises. This fundamental property is what allows thermistors to be used for precise temperature measurements and control in various electronic circuits. Their ability to provide a measurable change in resistance with temperature means they can be effectively used in applications such as temperature sensors, temperature compensation, and circuit protection.

In contrast, components that change capacitance with temperature, such as capacitive temperature sensors, and those that change inductance, like certain types of inductors, do not classify as thermistors. Maintaining a constant resistance would contradict the defining feature of a thermistor, as it is precisely the variable resistance that enables its function in temperature measurement and control.