Definitions for "Ringfort"
an early medieval earthwork fortification, usually built between AD 500-1000
Ringforts are fortified settlements that are generally agreed to be from the Early Medieval Period in Northern Europe, especially Ireland. They are also known as ráth, caiseal, cathair and dún in the early Irish sources. A ráth (anglicised rath), was made of earth, caiseal (northwestern Ireland, anglicised cashel) and cathair (southwestern Ireland) were built of stone.