A pot (potentiometer) is a 3 terminal resistor. It has a connection to each end of a resistive element and a third connection to a sliding contact that can connect anywhere from end to end on the element. If the element is connected across a voltage (potential difference) the slider can produce any potential between those connected to the ends.
A variable resistor (rheostat) has two connections - one end of a resistive element and the sliding contact that puts more or less resistance between itself and the end contact.
Your device sounds like a selector switch that shorts a 100 ohm resistor with a contact in one position and opens that short in the other position. Any light switch and a 100 ohm resistor could do the same thing.