Zeeman, Pieter (pēˈtər zāˈmän) [key], 1865–1943, Dutch physicist. He was professor of physics at the Univ. of Amsterdam from 1900 and director of the Physical Institute, Amsterdam, from 1908. In 1896 he discovered the Zeeman effect. He shared the 1902 Nobel Prize in Physics with H. A. Lorentz. His works include Researches in Magneto-Optics (1913).