The Gaelic word for grandma is Maimeó (MAM-o). Alternate spellings include Mamó and Mahmó. This term could also be translated as "granny." Another Gaelic term of endearment for a grandmother is Móraí (MO-ree).
Maimeó and móraí are both terms that would be used to address a grandmother directly and informally. The Gaelic word for grandmother is seanmháthair (shan a WAW her). Other spellings of this term include: seanmhair, seanmathair and seanmathair. This term translates literally to "old mother" and is not often used to refer to a grandmother directly. Other ways to refer to a grandmother include máthair mhór (maw her aWOR) and máthair chríona (MAW her KHREE un na), which translate to "great mother" and "wise mother," respectively. Máthair mhór and máthair chríona, like seanmháthair, are more formal terms. The Gaelic term for great grandmother is sin-seanmháthair.
Gaelic children also use the term móraí to refer to their grandfathers. Another informal term for grandfather is daideó (DADJ-oh). The formal term for grandfather is seanathair. In Irish culture, children are frequently named after their grandparents. Grandparents tend to have great influence in the lives of their grandchildren.
Irish children still use Gaelic terms to refer to their grandparents, but the term has not expanded past Gaelic culture in the way that other terms have, such as the Italian Nonna or the German Oma. This is probably due to the difficulty of pronunciation.