This is the 5077th most frequent Russian word.
мое
"Мое" means "my" or "mine" in English.
'Мое' is used here as a singular masculine possessive pronoun agreeing with 'хобби' (hobby, neutral gender).
Это мое любимое хобби.
This is my favorite hobby.
'Мое' acts as a singular neutral possessive pronoun agreeing with 'сердце' (heart, neutral gender).
Мое сердце наполнено радостью.
My heart is filled with joy.
'Мое' is a singular neutral possessive pronoun modifying 'мнение' (opinion, neutral gender).