A bullaun is a large stone, usually a boulder or a slab, into which one or more cup-shaped depressions have been carved or worn. The water that collects in these hollows has long been considered to have curative or protective properties, and bullauns are frequently found near early Christian sites, churches, and holy wells, though their origins may well be considerably older. The Killimor example belongs to this widespread but still somewhat mysterious class of monument, objects that sit at the boundary between the archaeological and the devotional, between the measurable and the believed.

Bullaun stones are found across Ireland in considerable numbers, and their associations are varied. Some were used as cursing stones, rotated counter-clockwise to bring misfortune on an enemy. Others were simply part of the ritual fabric of a local sacred site, their hollows filled by rain and visited by those seeking relief from ailments, particularly of the eyes or skin. The east Galway landscape around Killimor has its own layered early medieval history, and the presence of a bullaun here fits a broader pattern of such stones appearing in areas with documented ecclesiastical or monastic activity, though the precise context of this particular stone remains unrecorded in any detail currently available.