This is the 1122nd most frequent Polish word.
pozostają
"Pozostają" means "they remain" or "they stay."
Here, 'pozostają' is used in the present tense to indicate the continuous action of staying in one place.
Pozostają w domu, ponieważ pada deszcz.
They are staying at home because it is raining.
In this sentence, 'pozostają' expresses the maintenance of a relationship over time.
Nawet po wielu latach pozostają przyjaciółmi.
Even after many years, they remain friends.
Here, 'pozostają' implies something being left in a certain state.