Éogan is an early Irish male given name, which also has the hypocoristic and diminutive forms Eoganán, Eóghainin, Eóghain and Eóghainn.
[1][2][3] The Corpus Inscriptionum Insularum Celticarum derives Eógan from the Primitive Irish *Iwagenas,[4] while others such as Tomás Ua Concheanainn (Mion-chomhradh, in 1903) have stated that Eóghan equates to Owain and Eugene;[1] Dr Rachel Bromwich has commented that Eoghan is a derivation of the Latin Eugenius,[3] making these names long-attested in Gaelic areas, yet still based on loan-words.
[2] Eoghan has also been translated into English as "well born", in an example c. 1923, due to this Latin derivation, with the note that in common usage it is usually anglicised to "Eugene".
[5] The name corresponds to the Welsh Owain, often spelt Owen in English;[1][2] as well to Ewen, Ewan and Euan.
The most likely and widely accepted origin of the Old Welsh Owain is, like the Old Irish Eogan also from Latin Eugenius.