When do you put an O or A before the words Meu or Minha in Brazilian Portuguese?

Answer 1

When the substantive is masculine you have to use "O" > (O meu carro é vermelho)

O touro, o caminhão, o homem, o livro, etc.

When the substantive is feminine you have to use "A" > (A minha casa é grande)

A vaca, a máquina de costura, etc.

When the substantive is feminine, like zebra, onça, etc, you must write "A zebra macho, A zebra fêmea," " A onça macho, A onça fêmea," because they are feminine substantives, but when you need to quote their gender use macho and fêmea after the substantive.

When it is a masculine gender like leopardo, and you want to quote its gender you must write "o leopardo fêmea, o leopardo macho"

Sometimes you needn't to use A or O before minha or meu. ( Minha terra tem palmeras onde canta o sabiá) (Meu carro é novo) because the article is implicit in the sentence. Terra is a feminine substantive, therefore the article only would be "A".

Answer 2

The choice between using "o" or "a" before the words "meu" or "minha" in Brazilian Portuguese depends on the gender of the noun that follows. If the noun is masculine, you use "meu" with "o" (e.g., meu livro), and if the noun is feminine, you use "minha" with "a" (e.g., minha casa).