Wikipedia
Eógan
Éogan or Eógan is an early Irish male name, which also has the hypocoristic and diminutive forms Eóganán, Eóghainin, Eóghain and Eóghainn. In more modern forms of Irish it is written as Eóghan or Eoghan. The name is often associated with the Greek name Eugenes, meaning noble born. Etymologists disagree as to the origin of Eoghan. The encyclopedia Irish Names (1981, 1990) derives the name Primitive Irish *Iwagenas, while others such as Tomás Ua Concheanainn (Mion-chomhradh, 1903) have stated that Eóghan equates to Owain and Eugene, and Dr. Rachel Bromwich have commented that Eoghan is a derivation of the Latin Eugenius.
The name corresponds to the Welsh Owain, often spelt Owen in English; as well to Ewen, Ewan and Euan.