This is the 9610th most frequent Portuguese word.
contêm
"Contêm" means "contain."
Here, 'contêm' refers to the third-person plural present indicative form of the verb 'conter', meaning 'to contain'. It describes what is held within the books.
Os livros na prateleira contêm muitas informações valiosas.
The books on the shelf contain a lot of valuable information.
In this sentence, 'contêm' is similarly used as the third-person plural for stating what is stored or present inside the boxes.
As caixas no depósito contêm materiais recicláveis.
The boxes in the warehouse contain recyclable materials.
Again, the third-person plural form of 'conter' is used here to explain what is included within the documents.