This is the 812th most frequent Russian word.
остальные
"The rest" or "the others."
The word "остальные" is used to mean "the others" in the sense of those remaining or not included in a prior action or description.
Они уже ушли, а остальные ещё здесь.
They have already left, but the others are still here.
Here, "остальные" means "the rest" as items not selected or excluded.
Я взял только нужные документы, а остальные оставил дома.
I only took the necessary documents, and left the rest at home.
The term "остальные" is used here to mean "remaining," referring to a part of a group that has not yet arrived.