From TalkBass Wiki
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.
