a city of Germany, in the duchy of Holstein, in the circle of Lower Saxony, and the residence of the duke of Holstein-Gottorp. It has a castle, and a university founded in 1665; and there is a very celebrated fair held here. It is seated at the bottom of a bay of the Baltic sea called Kielvorwerk, at the mouth of the river Schwentin, in E. Long. 10. 17. N. Lat. 54. 26.