cúigiú

Etymology
From, from , from. . In northern dialects (Ulster and Mayo) the historical form and the modern form  are homophonous, so the modern form can be considered simply a respelling to assimilate the word to the ordinal suffix. In the dialects of Galway and Munster the modern form may be considered to have replaced the historical form, which was pronounced.

Adjective

 * 1) fifth

Noun

 * 1) a fifth