Tearmann Caithreach, in County Mayo, carries within it the Old Irish word tearmann, meaning a sanctuary or church land, the kind of protected zone that once surrounded an early medieval monastery and offered legal refuge to those who reached its boundary. The second element, caithreach, suggests an association with a city or principal settlement, though in early Irish usage the word could describe an important ecclesiastical site rather than anything urban in the modern sense. That an enclosure monument is recorded here points to something physically surviving in the landscape, a boundary of some kind, whether earthen bank, ditch, or curving field margin, that may preserve the outline of that original sacred precinct.