This is the 244th most frequent German word.
geworden
"Geworden" means "become" or "turned into" (past participle of "werden").
In this sentence, "geworden" is the past participle of "werden" used to express a change or transformation in someone's profession or status.
Er ist Arzt geworden.
He has become a doctor.
Here, "geworden" is used to indicate a change in the state of the environment, specifying how it transitioned over time.
Es ist dunkel geworden.
It has become dark.
In this example, "geworden" describes the transformation of the relationship between individuals into friendship.