Word of the Day
9 February 2026
rheostat
An electrical resistor with two terminals, the resistance of which can be varied continuously by moving a knob or slider to regulate the flow of an electric current.
Why this one
The name is built from Greek for a flowing stream, plus a root meaning to hold steady, so it reads as current governor. A potentiometer wired with only two terminals does the same job, which is why the two names get swapped; the difference is that a rheostat burns the surplus off as heat, which is why solid state drives took over the heavy work.
In use
That old test bench still has a rheostat on the load bank, and you can feel it cooking after ten minutes at full draw.
Written by our editors to show how the term is used, not a recorded quotation.