diamhair Definitions (by source) Show all Poems on the O'Reillys hidden, secret, dark. As subst. 'a hidden place': cairthi diamhra an dúin. the innermost pillar of the fortress, 1763. Poems on the O'Reillys. Editor: James Carney. Stories from Keating's History of Ireland dark, secret; as subst., secret part, recess. Stories from Keating's History of Ireland. Author: Geoffrey Keating. Editor: Osborn Bergin. The Book of O'Hara: Leabhar Í Eadhra (37), dul i nd. go into hiding 1023; i ndiamhraibh in secret places 1433; gach diamhair dá fhréimh secret about his stock 491. The Book of O'Hara: Leabhar Í Eadhra. Editor: Lambert McKenna S.J.