Is the word boca the same in Brazilian and European Portuguese?

No

While the anatomical meaning of "boca" (mouth) is identical in both varieties, there are differences in typical usage, idiomatic meaning, and grammar. In Brazil, "boca" is frequently used in the specific idiom "boca de fumo" to refer to a drug den. In Portugal, "boca" is commonly used to mean a sarcastic or snide remark (e.g., "mandar uma boca"). Additionally, the pronunciation differs significantly; European Portuguese features much heavier vowel reduction, whereas Brazilian Portuguese maintains more distinct, open vowel sounds. There is also a grammatical difference in how the word is used in commands, as Brazilians typically use the third-person singular (você) while Portuguese people often use the second-person singular (tu).

Brazilian Portuguese Examples

1. Abra a boca para o exame. (Open your mouth for the exam.)
2. Ele está com a boca suja de chocolate. (He has chocolate all over his mouth.)
3. Mantenha a boca fechada sobre o segredo. (Keep your mouth shut about the secret.)
4. A polícia fechou a boca de fumo. (The police closed the drug den.)
5. A entrada tem uma boca larga. (The entrance has a wide opening.)

Portuguese (Continental) Examples

1. Abre a boca para o exame. (Open your/your mouth for the exam.)
2. Ele está com a boca suja de chocolate. (He has chocolate all over his mouth.)
3. Não digas nada, mantém a boca fechada. (Don't say anything, keep your mouth shut.)
4. A polícia fechou o ponto de venda. (The police closed the drug selling point.)
5. A entrada tem uma abertura larga. (The entrance has a wide opening.)