This is the 13578th most frequent German word.
dereinst
"Dereinst" means "one day" or "someday" in the future, or "once" in the past.
Used to signify a point in the future.
Dereinst werde ich die Welt bereisen.
One day, I will travel the world.
Used to refer to a point in the past.
Man erzählt Geschichten über Helden, die dereinst Großes vollbracht haben.
People tell stories about heroes who once accomplished great deeds.
Used to indicate a hopeful future condition or outcome.