The name, sometimes translated loosely as "cooking place of the deer" or "cooking pit of the Fianna," refers to a type of Bronze Age site typically consisting of a horseshoe-shaped mound of fire-cracked stone, built up over centuries of repeated use beside a water source. The working principle was straightforward: stones were heated in a fire, then dropped into a water-filled trough, raising the temperature enough to cook meat or, as some researchers have argued, to serve other purposes entirely, from textile processing to bathing.

The Bronze Age origins of most fulachtaí fia place them roughly between 1500 and 500 BC, though some sites have returned dates as early as the third millennium BC. The distinctive mounds survive because the shattered, heat-stressed stone is of no particular use for building or agriculture, so it tends to get left alone. In that sense, the monument at Treanybrogaun owes its survival less to any protective instinct than to the simple fact that nobody had a pressing reason to clear it away. The townland name itself, like many in the west of Ireland, preserves a Gaelic description of the landscape, though its exact meaning in this case is not readily parsed from standard sources.

The site sits within a county that has one of the densest concentrations of fulachtaí fia in Ireland, a reflection both of Mayo's wet, boggy terrain, which preserved such features exceptionally well, and of the sheer intensity of Bronze Age activity across the region. For a monument type so thoroughly unremarkable in appearance, a low, curved spread of dark, fragmented stone in rough ground, the cumulative picture they offer of prehistoric life is considerable.