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

Yes

The spelling, grammar, and meaning of "reuniões" are identical in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, the vowels tend to be more "open" and clearly articulated. In Continental Portuguese, unstressed vowels are often more "closed" or even reduced (shortened), which can make the word sound slightly more clipped to a Brazilian ear.

Brazilian Portuguese Examples

1. Eu tenho muitas reuniões hoje. (I have many meetings today.)
2. As reuniões de condomínio são chatas. (Condo meetings are boring.)
3. As reuniões de trabalho atrasaram. (Work meetings were delayed.)
4. Gosto de fazer reuniões rápidas. (I like to have quick meetings.)
5. Temos várias reuniões na semana. (We have several meetings during the week.)

Continental Portuguese Examples

1. Tenho várias reuniões hoje. (I have several meetings today.)
2. As reuniões de condomínio são aborrecidas. (Condo meetings are boring/annoying.)
3. As reuniões de trabalho sofreram um atraso. (Work meetings suffered a delay.)
4. Prefiro fazer reuniões curtas. (I prefer to have short meetings.)
5. Temos reuniões agendadas para a semana. (We have meetings scheduled for the week.)