A bullaun is a large stone, usually boulder-sized, into which one or more rounded depressions have been ground or worn, creating shallow basins that collect rainwater. They are found across Ireland in their hundreds, often near early medieval ecclesiastical sites, and their original purpose remains genuinely uncertain. Some were likely used for grinding or pounding, in the way a mortar works. Others accumulated folklore over centuries, their water held to have curative or cursing properties depending on the tradition, and many were treated as sacred objects long after the communities that first shaped them had gone.

The presence of a bullaun in Derrydonnell More places it within a part of Galway with a layered early Christian past, a region where ringforts, church sites, and holy wells appear with some regularity in the landscape. The name Derrydonnell derives from the Irish, and the townland sits in territory that would have been worked and inhabited continuously from at least the early medieval period. Bullauns associated with church sites were sometimes used in baptismal or blessing rituals, and those found in more isolated field settings may represent the remnants of a once larger complex, the church itself long since collapsed or cleared away.