This is the 13265th most frequent Russian word.
монастыре
"Монастыре" is the prepositional case of "монастырь," meaning "monastery."
Here, 'монастыре' is used in the prepositional case to denote place.
Я жил в монастыре три дня.
I stayed in the monastery for three days.
In this sentence, 'монастыре' is used in the prepositional case because it's part of the phrase 'о жизни в', which requires this case to express location in context.
Он рассказывал о жизни в монастыре.
He was talking about life in the monastery.
Here, 'монастыре' is used in the prepositional case to inquire about a person's location.