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.

do you mean "the meaning of fort" ? the meaning is: 1) a building built in order to defend an area against attack 2) a place where soldiers live and have their training according to wikipedia: "From very early history to modern times, walls have been a necessity for many cities. Uruk in ancient Sumer (Mesopotamia) is one of the world's oldest known walled cities. Before that, the city (or rather proto-city) of Jericho in what is now the West Bank had a wall surrounding it as early as the 8th millennium BC. The Ancient Egyptians also built fortresses on the frontiers of the Nile Valley to protect against invaders from its neighboring territories. Many of the fortifications of the ancient world were built with mud brick, leaving many no more than mounds of dirt for today's archaeologists." ciao =)