This is the 519th most frequent Portuguese word.
nossos
"Our" (plural).
The word 'nossos' is used here as a possessive adjective to indicate that the books belong to us.
Nossos livros estão na mesa.
Our books are on the table.
In this sentence, 'nossos' is a possessive adjective modifying 'amigos,' indicating they are our friends.
Vamos cuidar dos nossos amigos.
Let's take care of our friends.
Here, 'nossos' shows possession, referring to the efforts that belong to us.