Hi, Fede's definition of Fort is correct. According to google, Rmíz is the oldest fort in the world with a stone faced rampart and it's significant in the Neolithic/Copper Age Moravian landscape.
The hilltop fort called Rmíz in the Czech Republic, is the oldest fort in a long chain of eleven similar central sites dotting the Early Neolithic/Copper Age Moravian landscape. Strategically located, the site was built in the earliest phase of the Funnel Beaker Culture's Baalberg Group (4000/3800-3600/3500 cal. BC). It was constructed in an area where several cultures overlap. The fort's earliest construction phase consists of the first stone-faced rampart in Central/Northern Europe. There are traces of copper production, including slag. Three tomb clusters with dozens of long-mounds and tumuli yielded textile fragments and evidence of changes in burial practices.