Low resistance pots are normally called rheostats and are wire-wound (no use at RF).
A rheostat is a variable resistor and generally needs only 2 terminals. It provides no potential divider capability. Certainly rheostats are generally of low resistance but that does not mean low resistance potentiometers should be called rheostats.
Rheostats are generally linear devices but can be obtained with a nonlinear function.
A potentiometer (whatever its resistance value) has at least 3 terminals (some have a fourth fixed value terminal at mid scale 50%) and provide a potentiometric divider function. Track resistance can be logarithmic, anti-logarithmic or linear.
Potentiometers can act as rheostats by using one end terminal and the slider terminal. It is generally good practice to also connect the "unused" end resistance terminal to the slider. This ensures there is always a resistance in circuit even if the slider contact goes open circuit.