Coined after the Fender pickup in the first popular mass produced electric bass guitar (Precision was in reference to the accuracy of play possible from the fretted neck - since its acoustic predecessors were fretless). The initial single pole pickup gave way to an improved version that was a humbucker split into two single flat coil staggered halfs with bi
-pole magnets as it's known today. Generally known for a deep, thumpy tone.