This is the 441st most frequent Serbian word.
остали
"Остали" means "the others" or "the rest" in English.
Here, 'остали' is used as a noun to mean 'the others'.
Остали су отишли кући.
The others went home.
In this sentence, 'остали' acts as an adjective modifying 'људи', to mean 'other'. It specifies a subset within the group of people.
Остали људи на забави су плесали.
The other people at the party were dancing.
Here, 'остали' is part of the verb phrase 'остати', meaning 'to be left without' or 'to end up with/out something'.