This is the 8079th most frequent German word.
ir
"Ir" is not a standalone word in standard German.
In this sentence, "ihr" is used as the dative pronoun for "she" referring to the recipient of the book.
Ich gebe ihr das Buch.
I give her the book.
In this sentence, "ihr" is used as a possessive pronoun for "she," describing ownership of the house.
Ihr Haus ist groß.
Her house is big.
In this sentence, "ihr" is used as the second person plural pronoun "you," addressing a group of people.