The term, sometimes rendered as fulacht fiadh, refers to a type of prehistoric cooking site found in enormous numbers across Ireland, more than four thousand of them recorded to date. The typical form is a horseshoe-shaped mound of fire-cracked stones, built up over repeated use beside a water source. The working principle was straightforward: stones were heated in a fire, then dropped into a water-filled trough, bringing it to a boil. Food, very likely meat, was then cooked in the heated water. The sites cluster in low-lying, boggy ground, which is partly why so many have survived, sealed under peat, and partly why they remain easy to overlook.