Schloss (pl. Schlösser) is a German word for a building similar to a château, palace or manor house; or what in the British Isles would be known as a stately home. Most Schlösser were built after the Middle Ages as residences for the nobility and not as true fortresses, although they were often originally fortified; the usual German term for a true castle is Burg and for a fortress is Festung; however, many castles were called "Schloss", especially those that were used as residences after they lost their defensive significance and many were adapted to new tastes during the Renaissance and Baroque period.
Examples of Schlösser 
|Look up schloss in Wiktionary, the free dictionary.|
In another context schloss is also the German word for a lock.