The word doonbullaun, sometimes rendered as dunbullaun or dún bolláin, combines the Irish for fort or enclosure with bolláin, meaning a rounded hollow worn into stone. These cup-shaped depressions, ground into boulders or rocky outcrops over centuries, are among the more enigmatic features of the Irish early medieval landscape. They appear near monastic sites, at holy wells, and beside the remains of ringforts, and while theories about their use range from the liturgical to the practical, no single explanation has settled the matter. The association with a dún suggests that whatever stone or enclosure gave this townland its name, it was considered significant enough to anchor the place in local memory.

The Moyour Channel itself runs through a landscape shaped by the slow recession of water, a region where turf, tidal influence, and the remnants of older boundaries have layered one on top of another over millennia. Mayo's western parishes contain a remarkable density of early Christian and prehistoric remains, many of them only partially catalogued, and sites carrying the bolláin element are typically associated with patterns of devotional activity that continued well into the post-medieval period. The precise character of this particular site, whether a boulder with worn hollows, the ghost of a small enclosure, or something more substantial, remains difficult to establish from what has survived in the record.