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

Yes

The word "cidadão" is identical in meaning, grammar (including the plural "cidadãos"), and spelling in both Brazilian and Continental Portuguese. The only differences lie in pronunciation:

• Brazilian Portuguese: The pronunciation is generally more "open" and melodic. The unstressed vowels are more clearly articulated, and in many Brazilian regions, the "d" in the middle of the word might be pronounced with a "dj" sound (palatalization), though in formal speech, it remains a standard [d].
• Continental Portuguese: The pronunciation is more "closed" and stress-timed. Unstressed vowels are often reduced or almost swallowed, making the word sound more clipped and denser to a Brazilian ear.

Brazilian Portuguese Examples

1. Todo cidadão tem o direito de votar. (Every citizen has the right to vote.)
2. Ele é um cidadão muito exemplar. (He is a very exemplary citizen.)
3. Precisamos de cidadãos mais conscientes. (We need more conscious citizens.)
4. O papel do cidadão é fiscalizar o governo. (The citizen's role is to monitor the government.)
5. Como cidadão, eu me sinto responsável pela minha rua. (As a citizen, I feel responsible for my street.)

Continental Portuguese Examples

1. É um dever de cada cidadão respeitar as leis. (It is the duty of every citizen to respect the laws.)
2. O cidadão deve estar atento aos seus direitos. (The citizen must be attentive to their rights.)
3. Trata-se de um direito fundamental do cidadão. (It is a fundamental right of the citizen.)
4. O bom cidadão contribui para a sua comunidade. (The good citizen contributes to their community.)
5. O Estado tem o compromisso de proteger o cidadão. (The State has the commitment to protect the citizen.)