Where does “Eleni” come from?

Eleni is an English form of Ancient Greek Ἑλένη, a name of unknown ultimate origin that appears in Greek mythology and literature from early attestation.

Ancestry of “Eleni”, step by step

Eleni traces back through 3 separate lines of ancestry.

via Ancient Greek Ἕλλην

StepLanguageWordMeaning
1Ancient GreekἝλληνGreek, one who is from Greece or speaks Greek;...
2Ancient GreekἙλλοίThe Greeks in Dodona
3Ancient Greekἕλλαseat
4Proto-Hellenic*héllā

via Greek Ελένη

StepLanguageWordMeaning
1GreekΕλένηHelen
2Ancient Greekἑλένηtorch, firebrand; corposant, St. Elmo's fire;...
3Proto-Indo-Europeanswel-to smolder; burn; scorch; beam, board, frame,...

via Proto-Celtic so

StepLanguageWordMeaning
1Proto-Celticsothis
2Proto-Indo-Europeanthis; that
Every word from Proto-Hellenic *héllāEvery word from Ancient Greek ἕλλαEvery word from Ancient Greek Ἑλλοί