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

Yes

The word "regra" is identical in both Brazilian and European Portuguese regarding its meaning (rule, regulation, or norm), spelling, and grammatical gender (feminine). The only differences are in pronunciation. In Brazilian Portuguese, the pronunciation of the vowels and the "r" can vary significantly depending on the region (e.g., the "e" may be more open), whereas in European Portuguese, unstressed vowels are often more reduced or "swallowed," and the "r" is typically more uvular.

Brazilian Portuguese examples:

1. A regra é clara: não pode entrar. (The rule is clear: you can't enter.)
2. Eu sigo todas as regras do jogo. (I follow all the rules of the game.)
3. É regra da casa não usar o celular à mesa. (It's a house rule not to use the cell phone at the table.)
4. Eu quebrei uma regra sem querer. (I broke a rule by accident.)
5. Cada país tem sua própria regra. (Each country has its own rule.)

European Portuguese examples:

1. A regra é clara: não se pode entrar. (The rule is clear: one cannot enter.)
2. Sigo todas as regras do jogo. (I follow all the rules of the game.)
3. É regra da casa não usar o telemóvel à mesa. (It's a house rule not to use the mobile phone at the table.)
4. Quebrei uma regra sem querer. (I broke a rule by accident.)
5. Cada país tem a sua própria regra. (Each country has its own rule.)