Oisín (pr. o-sheen or aw-sheen) is the name of a mythological figure in Irish mythology, a great warrior and poet who was part of the Fianna; he was also the lover of a fairy woman named Niamh who took him away to Tir na nÓg (the land of the young) for 300 years before he returned to Ireland and died. Oisín was the son of Fionn mac Cumhaill (Finn MacCool) and Sadhbh (pr. sieve) who was turned into a deer by a dark druid when she refused his love. She gave birth to Oisín when she was a deer, who was found by Finn when he was searching the woods for his missing wife and recognized him as his son. His name means “little deer” or “fawn” from Irish os (deer) combined with the diminutive suffix -ín; os derives from Proto-Celtic *uxso (stag, ox) from PIE *uksḗn (bull).
Origin: Proto-Indo-European

Variants:
- Osheen (Irish)
- Ossian (Irish)
- Oisin (English)
- Osian (Welsh)
- Oisean (Scottish Gaelic)