The term refers to a type of prehistoric cooking place, found in great numbers across Ireland, typically comprising a horseshoe-shaped mound of burnt and shattered stone beside a trough and a hearth. Water would be boiled by dropping fire-heated stones into the trough, the stones cracking in the process and accumulating over time into the characteristic mound. At Knockbarry, even that mound is largely gone.

The site lay to the south-west of two wells, both now drained, and the association between fulachta fiadh and wet or marshy ground is a well-established pattern across Irish archaeology. Water supply was essential to how these sites functioned. At some point around 1969, according to local accounts, the mound was levelled, most likely during agricultural improvement works of the kind that quietly erased a great number of low-lying earthworks across the Irish countryside during the mid-twentieth century. When the site was later visited for recording purposes, adverse weather conditions prevented any burnt material from being identified at the surface, leaving the slight ground rise as the only physical evidence that anything had ever been there.