Gender Masculine Usage Irish, Irish Mythology Pronounced Pron. /ɔ.ˈʃiːnʲ/(Irish) /oʊ.ˈʃiːn/(English) Meaning & History Means "little deer", derived from Old Irish oss "deer, stag" combined with a diminutive suffix. In Irish legend Oisín was a warrior hero and a poet, the son of Fionn mac Cumhaill and the narrator in many of his tales.