The term refers to a deposit of fire-cracked stones, charcoal, and scorched soil, typically the remnant of a fulacht fiadh, a type of prehistoric cooking or industrial site found in enormous numbers across Ireland. The working theory is that stones were heated in a fire and then dropped into a water-filled trough to bring it to the boil, a process repeated until the stones cracked and were discarded. Over time, those discarded stones accumulated into the characteristic mounded or spread deposits that survive today.

Fulachtaí fiadh, as they are known collectively, are among the most common prehistoric monuments in the Irish landscape, with thousands recorded across the island. Most date to the Bronze Age, roughly 1500 to 500 BC, though some have yielded earlier dates. They tend to cluster near water sources, streams, or boggy ground, and their precise function remains a matter of genuine debate among archaeologists. Cooking is the most widely accepted explanation, but brewing, hide preparation, and bathing have all been proposed at various points. The Breahig example represents one such deposit, quietly preserved beneath the Kerry soil, its particular details, dimensions, and excavation history not yet available in the public record.