The Irish word "lios" refers directly to a ringfort, a type of enclosed settlement used throughout early medieval Ireland, roughly between the fifth and twelfth centuries. That the place-name has preserved this meaning for over a thousand years, while the earthwork itself endures in the ground beneath it, is the kind of quiet persistence that tends to go unnoticed.

Ringforts, known variously as raths or lios depending on regional tradition, were the most common form of rural settlement in early medieval Ireland. Typically circular, they consist of one or more earthen banks and ditches enclosing a domestic space that would once have held a farmstead, outbuildings, and occasionally a souterrain, an underground stone-lined passage used for storage or refuge. Kerry has a particularly dense concentration of these sites, and the survival of lios in a townland name like Lissodeige suggests the fort was prominent enough, and enduring enough, to define the landscape for the people who named it. The specific history of this particular fort, its construction date, the family or clan who occupied it, and the condition of its banks today, remains to be fully documented.