Potentiometers are usually referring to a voltage divider. They are typically bigger and easy to adjust, for situations where you anticipate changing it frequently. Because we’re lazy, we also call them "pots" a lot.
A three-terminal variable resistor used to vary the voltage between the center terminal and one of the outside terminals.
Grob’s Basic Electronics, 11th Edition by Mitchel E. Schultz
The potentiometer (or pot for short) is a three-terminal device that operates on the principle of voltage division.
Fundamentals of Electric Circuits, 5th Edition by Charles K. Alexander and Matthew N. O. Sadiku
A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.
The measuring instrument called a potentiometer is essentially a voltage divider used for measuring electric potential (voltage); the component is an implementation of the same principle, hence its name.
Potentiometers are commonly used to control electrical devices such as volume controls on audio equipment. Potentiometers operated by a mechanism can be used as position transducers, for example, in a joystick. Potentiometers are rarely used to directly control significant power (more than a watt), since the power dissipated in the potentiometer would be comparable to the power in the controlled load.