The name itself offers the first clue to its character. "Doon" derives from the Irish "dún", meaning a fort or enclosed settlement, a word that appears across the Irish landscape wherever ancient defensive or communal structures once stood. The second element, "glass", likely relates to a colour term in Irish, perhaps grey or green, though place-name meanings can shift and blur over centuries of use and transcription.

Beyond the name, the available record for Doonaglass is frustratingly thin. It is logged as an archaeological monument in County Mayo, a county whose landscape is dense with the physical residue of prehistoric and early medieval habitation, from ring forts and promontory forts to megalithic tombs and early Christian enclosures. The rough quarter, which is what An Cheathrú Gharbh translates to, suggests terrain that would have made both settlement and agriculture demanding work. Mayo's Atlantic-facing townlands are often boggy and boulder-strewn, and the communities that left their marks there did so in conditions that required considerable ingenuity and effort. A dún in such a landscape would typically have served as a defended farmstead or the seat of a local family of some standing, though without further excavation or documentation it is impossible to say more about what Doonaglass specifically represents.