The term, loosely translated as "wild deer cooking place," refers to the horseshoe-shaped mounds of fire-cracked stone and charcoal-rich soil that accumulate beside ancient troughs, where water was heated by dropping in stones made scorching hot in a nearby fire. The example at Killadangan in County Mayo is one of countless such sites recorded across the country, most of them dating to the Bronze Age, roughly 1500 to 500 BC, though some may be earlier or later.

The standard interpretation holds that these sites functioned as outdoor cooking facilities, the trough filled with water, the stones heated and dropped in until the water boiled, the food submerged and left to cook. But that consensus has been challenged over the decades. Experimental archaeology has suggested the troughs could equally have served for textile dyeing, leather working, or even bathing. No single explanation has settled the debate, and the ambiguity is part of what keeps fulachtaí fia interesting. The Killadangan site sits within a county that has produced a significant number of Bronze Age finds, owing in part to the boggy, low-lying terrain that preserves organic material and archaeological features with unusual fidelity.