This is the 248th most frequent Hungarian word.
közben
"Meanwhile" or "in the meantime."
Here, 'közben' indicates that the action of listening to music occurs simultaneously with cooking.
Ételt főztem közben zenét hallgattam.
I cooked food while listening to music.
Here, 'közben' provides a temporal adverbial sense, indicating an event occurring in the midst of other activities.
Közben megérkezett a postás.
Meanwhile, the postman arrived.
In this case, 'közben' describes interruptions happening during the time frame of the movie.