authoritative dictionary of the Irish language that continues, starting with the letter D, the work of Kuno Meyer's Contributions to Irish Lexicography (1906–07), which covered A–C.

Based, according to its subtitle, on Old and Middle Irish materials, it began publication in Dublin in 1913. The collection of the material, which is based on historic principles and will cover the language from its earliest period, has been administered by the Royal Irish Academy. Culled from books, manuscripts, and spoken language, entries describe the development of the meanings of words and their grammatical inflections.

In 1938 the academy began the irregular publication of fascicles continuing the work under the general heading Contributions to a Dictionary of the Irish Language. The academy's intent in issuing these fascicles was to make available immediately the enormous amount of material already collected and prepared for the final dictionary.