This is the 93rd most frequent Russian word.
него
"Him" or "his" (genitive/accusative form of "он").
The word 'него' (him) is part of the phrase 'у него', which is used in Russian to express possession, similar to 'he has'.
У него есть книга.
He has a book.
The word 'него' (him) shows its function as a pronoun in the accusative case, referencing a male individual.
Я видел его вчера возле парка.
I saw him yesterday near the park.
The word 'нём' (him) is the prepositional form of 'него', used with a preposition to indicate the object of thought.