This is the 1650th most frequent Swedish word.
ellen
"Ellen" is not a Swedish word; it is typically a personal name.
Here, 'eller' is used as a conjunction to present two options to choose between.
Ska du välja boken eller filmen?
Are you going to choose the book or the movie?
In this sentence, 'eller' connects two potential possibilities in the context of identifying someone.
Jag är inte säker om det var Anna eller Maria.
I'm not sure if it was Anna or Maria.
The word 'eller' is used to offer options, implying a freedom of choice between alternatives.