This is the 365th most frequent German word.
ihres
"Ihres" means "hers," "theirs," or "yours" (formal), depending on context.
Here, 'ihres' is the possessive pronoun for 'her' in the genitive case referring to 'Bruder'.
Dies ist das Buch ihres Bruders.
This is her brother's book.
In this sentence, 'ihres' is the possessive pronoun referring to 'neighbor' in the genitive case meaning 'their'.
Ich habe das neue Haus ihres Nachbarn gesehen.
I saw the new house of their neighbor.
Here, 'ihres' is used as a possessive pronoun denoting 'their' in the genitive case, referring to 'team'.