quadrupole

/K W AA0 D R UW1 P OW0 L/
noun
  1. 1

    A distribution of either electric charge or magnetization equivalent to two dipoles that point in opposite directions.

  2. 2

    A magnet with two north poles and two south poles, used to focus a beam of particles.

Source: https://en.wiktionary.org/wiki/quadrupole