In Irish, the prefix "Cill" denotes a church or early monastic cell, and the presence of a formal enclosure here suggests that this was once a bounded sacred precinct, the kind of circular or sub-circular earthwork that early Irish monks used to demarcate the spiritual and physical limits of their community from the surrounding landscape. These enclosures, many of them dating to the early medieval period, were not merely symbolic; they defined zones of sanctuary, organised the layout of communal religious life, and often sheltered timber or stone oratories, burial grounds, and the cells of individual monks.

Kilkeeran almost certainly takes its name from a saint called Ciarán, a common dedication in early Irish Christianity and one associated with several figures from the fifth and sixth centuries, most famously Ciarán of Clonmacnoise. How directly the local tradition connects to any particular saint is now difficult to establish with certainty, but the pattern of a named enclosure in a quiet Mayo townland fits a broader picture of early Christian settlement that spread across the west of Ireland during the monastic period, often leaving little above ground beyond the curve of an earthen bank or the faint outline of a boundary ditch.