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

No.

While the spelling and core meaning of "entendeu" (the third-person singular past tense of entender) are identical, there are differences in grammar and typical usage. In Brazil, "entendeu" is the standard way to address "você" (the common second-person pronoun) in both informal and semi-formal contexts. In Portugal, however, when addressing a friend or peer informally, the pronoun "tu" is used, which requires the conjugation "entendeste." Additionally, while "entender" is used in both countries, a person from Portugal would much more naturally use the verb "perceber" to express the same idea of comprehension.

Brazilian Portuguese Usage

1. Você entendeu o que eu disse? (Did you understand what I said?)
2. Ele não entendeu o motivo. (He didn't understand the reason.)
3. Entendeu, né? (Understood, right?)
4. Você entendeu a explicação? (Did you understand the explanation?)
5. Ninguém entendeu o que aconteceu. (Nobody understood what happened.)

Continental Portuguese Usage

1. Percebeste o que eu disse? (Did you understand what I said?)
2. Ele não percebeu o motivo. (He didn't understand the reason.)
3. Percebeste, não foi? (Understood, wasn't it?)
4. Percebeste a explicação? (Did you understand the explanation?)
5. Ninguém percebeu o que aconteceu. (Nobody understood what happened.)