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

Yes.

The word "comiam" is identical in meaning, grammar, and spelling in both Brazilian and European Portuguese. It is the third-person plural imperfect indicative of the verb comer (to eat). The only difference is pronunciation. In Brazil, the unstressed vowels are generally more open and clearly articulated. In Portugal, there is a strong tendency toward "vowel reduction," where unstressed vowels (like the "i" in comiam) are pronounced more closed or are nearly swallowed, making the word sound much shorter.

Brazilian Portuguese Examples

1. Eles comiam pizza toda sexta-feira. (They used to eat pizza every Friday.)
2. As crianças comiam muito doce. (The children used to eat a lot of sweets.)
3. Vocês comiam o café da manhã na escola. (You all used to eat breakfast at school.)
4. Meus avós comiam pão com manteiga. (My grandparents used to eat bread with butter.)
5. Os pássaros comiam as sementes no jardim. (The birds used to eat the seeds in the garden.)

European Portuguese Examples

1. Eles comiam pizza todas as sextas-feiras. (They used to eat pizza every Friday.)
2. As crianças comiam muitos rebuçados. (The children used to eat many candies.)
3. Vocês comiam o pequeno-almoço na escola. (You all used to eat breakfast at school.)
4. Os meus avós comiam pão com manteiga. (My grandparents used to eat bread with butter.)
5. Os pássaros comiam as sementes no jardim. (The birds used to eat the seeds in the garden.)