An ogee arch is a curved form tapering to a point at the top, characteristic of later medieval ecclesiastical and domestic stonework in Ireland. The spandrels, the roughly triangular spaces flanking the arch head, carry carved decoration, which places this piece above ordinary structural salvage and into the category of considered craftsmanship.

The fragment sits immediately beneath the north side of the east window embrasure, which suggests it was deliberately incorporated during a phase of construction or repair rather than simply dumped as rubble fill. That kind of reuse was common enough in Irish church building, where dressed stone from an earlier structure on the same site, or occasionally from a nearby ruin, was folded into new work as a practical economy. The ogee form and carved spandrels point to medieval origins, though the precise date and source of the piece are not recorded. What the fragment implies is a layered building history at Patrickswell, with at least one earlier phase of architectural ambition now largely absorbed into the fabric of what survives.