Zeeman effect

Century Dictionary and Cyclopedia

1. n. See effect.

Wiktionary

1. n. physics the splitting of single spectral lines into three (or more) in the presence of a magnetic field

GNU Webster's 1913

1. (Physics) The widening and duplication, triplication, etc., of spectral lines when the radiations emanate in a strong magnetic field, first observed in 1896 by P. Zeeman, a Dutch physicist, and regarded as an important confirmation of the electromagnetic theory of light.