An Etymological Dictionary of Astronomy and Astrophysics

A set of either two → electric dipoles or two → magnetic dipoles in close proximity to each other arranged with alternating polarities and acting as a single unit. Quadrupole interactions are much smaller than dipole interactions, but can allow transitions forbidden in dipole moment transitions.

Etymology (EN): From L. quadru-, variant of quadri- “four” + → pole, on the model of → dipole.

Etymology (PE): Cahâr, → four, + qotb, → pole + noun/nuance suffix -é.