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

No

The difference between the two lies in spelling and pronunciation. In Brazilian Portuguese, the word is spelled cerimônia, using a circumflex accent to indicate a closed "o" sound [o]. In Continental (European) Portuguese, the word is spelled cerimónia, using an acute accent to indicate a more open "o" sound [ɔ]. While the fundamental meaning of the word is identical in both dialects, the distinction in accentuation changes how the vowel is articulated.

Brazilian Portuguese Examples

1. A cerimônia de casamento foi linda. (The wedding ceremony was beautiful.)
2. Não precisa de tanta cerimônia comigo. (You don't need so much formality with me.)
3. A cerimônia de formatura começa às oito horas. (The graduation ceremony starts at eight o'clock.)
4. Ele sempre faz muita cerimônia para pedir desculpas. (He always makes a big deal when apologizing.)
5. A cerimônia de premiação foi transmitida ao vivo. (The awards ceremony was broadcast live.)

European Portuguese Examples

1. A cerimónia do casamento foi linda. (The wedding ceremony was beautiful.)
2. Não precisas de tanta cerimónia comigo. (You don't need so much formality with me.)
3. A cerimónia de entrega de diplomas começa às oito horas. (The diploma ceremony starts at eight o'clock.)
4. Ele faz sempre muita cerimónia para pedir desculpa. (He always makes a big deal when apologizing.)
5. A cerimónia de entrega de prémios foi transmitida ao vivo. (The awards ceremony was broadcast live.)