The name, loosely translated from Irish as "wild deer cooking place," points to one long-held theory about their function, though the cooking interpretation has itself been contested and refined over the years. What remains consistent is the physical form: a horseshoe-shaped mound of burned and shattered stone, typically found near a water source, surrounding a trough that was once lined with wood or clay.

The standard explanation runs something like this. A trough was filled with water, stones were heated in a nearby fire, and those stones were dropped into the trough to bring the water to a boil. The repeated heating and cooling cracked the stones, and the discarded fragments built up into the characteristic mound over time. Most fulachtaí fia date to the Bronze Age, roughly between 1500 and 500 BC, though some have earlier or later origins. Their precise purpose continues to generate debate; brewing, textile processing, and bathing have all been proposed alongside the cooking theory, and experimental archaeology has demonstrated that several of these functions are practically plausible. The Shallee site sits within a county that contains numerous such monuments, Clare's varied terrain of limestone plain and bogland offering the wet, low-lying ground these features seem consistently to favour.