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

Yes

The meaning, spelling, and grammatical function of the word "magro" are identical in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, the final "o" is typically reduced to an "u" sound (sounding like magru), and the "r" can vary significantly by region (from a tap to a retroflex "caipira" R). In Continental Portuguese, the vowels are more clearly articulated with less reduction, and the "r" is typically a standard alveolar tap.

Brazilian Portuguese Examples

1. Ele ficou muito magro depois da dieta. (He became very thin after the diet.)
2. Meu irmão é magro e alto. (My brother is thin and tall.)
3. O cachorro está muito magro. (The dog is very thin.)
4. Eu não sou magro, sou forte. (I am not thin, I am strong.)
5. Ela sempre foi magra. (She has always been thin.)

Continental Portuguese Examples

1. Ele ficou muito magro após a dieta. (He became very thin after the diet.)
2. O meu irmão é magro e alto. (My brother is thin and tall.)
3. O cão está muito magro. (The dog is very thin.)
4. Eu não sou magro, sou forte. (I am not thin, I am strong.)
5. Ela sempre foi magra. (She has always been thin.)