Grania is a Latinized form of Gráinne, an Irish female name of uncertain meaning though it could be derived from Old Irish grán meaning “grain” via Proto-Celtic *grānom derived from PIE *ǵr̥h₂nóm (grain). Another possible etymology is from Scottish Gaelic gráidh, the genitive singular of gràdh (love) or even from Old Irish grían (sun). Grania is also the name of a gens (the name of a Roman clan) though I couldn’t find anything behind the name in Latin, or what it’s origin is.
In Irish mythology, Gráinne was engaged to Fionn Mac Cumhaill, leader of the Fianna and much older than her in age. She instead eloped with one of his warriors, Diarmuid Ua Duibhne (Diarmid O’Dyna) and the two were on the run from Fionn until he eventually forgave them and they settled down in a quiet spot and had five children. Eventually, Fionn organized a boar hunt and Diarmuid was included, though he was mortally wounded. Fionn could have saved him since water held in his hands had healing properties but he delayed it until it was finally too late and Diarmuid died.
- Granya (Irish)
- Gráinne (Irish)
- Grainne (English)