This is the 2693rd most frequent Russian word.
арина
"Арина" is a Russian female given name equivalent to "Arina" or "Irene" in English.
Here, 'Арина' is a proper name used as the subject of the sentence.
Арина любит читать книги.
Arina loves reading books.
'Арина' is used as a proper name indicating someone's name.
Его сестру зовут Арина.
His sister's name is Arina.
'Арина' is once again a proper name, functioning as the subject for this sentence.