This is the 33rd most frequent Greek word.
όταν
The Greek word "όταν" means "when."
'Όταν' is used as a conjunction introducing a temporal clause in the past.
Όταν έβρεχε, μέναμε στο σπίτι.
When it was raining, we stayed at home.
'Όταν' here introduces a future-time dependant temporal clause.
Όταν συναντήσω την Άννα, θα της πω τα νέα.
When I meet Anna, I will tell her the news.
This usage of 'όταν' introduces a general condition applicable to multiple instances in time.