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

Yes

The word "poloneses" is identical in spelling, meaning, and grammar in both Brazilian and Continental Portuguese. The only difference is in pronunciation:

• Vowel Reduction: In Continental Portuguese (Portugal), unstressed vowels are much more "reduced" or "swallowed." The 'e' sounds in poloneses will be very short, almost disappearing. In Brazilian Portuguese, the vowels are more "open" and clearly articulated.
• Sibilance: In Portugal, the 's' at the end of the word is almost always pronounced as a "sh" sound (/ʃ/), as in "shoe." In many parts of Brazil, the 's' at the end of words is often pronounced as a soft "s" sound (/s/), as in "sun."

Brazilian Portuguese Examples

1. Os poloneses estão chegando para a festa. (The Poles are arriving for the party.)
2. Eu gosto muito de pratos poloneses. (I like Polish dishes very much.)
3. Muitos poloneses moram no Brasil. (Many Poles live in Brazil.)
4. Você conhece aqueles poloneses? (Do you know those Poles?)
5. Os poloneses são muito trabalhadores. (The Poles are very hardworking.)

Continental Portuguese Examples

1. Os poloneses estão a chegar para a festa. (The Poles are arriving for the party.)
2. Eu gosto muito de pratos poloneses. (I like Polish dishes very much.)
3. Muitos poloneses vivem no Brasil. (Many Poles live in Brazil.)
4. Tu conheces aqueles poloneses? (Do you know those Poles?)
5. Os poloneses são muito trabalhadores. (The Poles are very hardworking.)