Alzey, a town in the grand duchy of Hesse, province of Rhenish Hesse, situated on the Selz, 18 m. S. by W. of Mentz; pop. in 1867, 5,358. The chief industries are tanning and the manufacture of tobacco. It was founded in the time of the Romans, and had for some time in the middle ages its own lords, ruins of whose castle are still extant.