Céiteamhain Definitions (by source) Show all Aithdioghluim Dána: A Miscellany of Irish Bardic Poetry, Historical and Religious, including the Historical Poems of the Duanaire in the Yellow Book of Lecan. Vol II, Translations, Notes, Vocabulary [10, 89], “May-day” 72 2; KM. Aithdioghluim Dána: A Miscellany of Irish Bardic Poetry, Historical and Religious, including the Historical Poems of the Duanaire in the Yellow Book of Lecan. Vol II, Translations, Notes, Vocabulary. Editor: Lambert McKenna S.J. Poems on the O'Reillys Maytime, 1290. As a masc. noun indecl., IGT, decl., 89, as a fem. noun like lánamhain, IGT 10 Poems on the O'Reillys. Editor: James Carney.