magnetorotation
noun
Rotation of the plane of polarization of electromagnetic waves under the influence of a magnetic field (N.E.D.'s lemma was spurious, and arose from a misreading of the New Sydenham Soc. Lexicon entry for Magneto-optic rotation, given in that work at Magneto-optic in the stylized form M.-rotation).
Origin
1930s. From German Magnetorotation.