* Menino: This is the most common and general term for a boy. It's used for young boys, similar to "boy" in English.
* Rapaz: This is more formal and can be used for a young man or a teenager. It's equivalent to "young man" or "lad" in English.
So, depending on the situation, you can choose either "menino" or "rapaz" to say "boy" in Portuguese.