This is the 10598th most frequent Russian word.
внуку
"Внуку" means "to the grandson" in English.
Here, the word 'внуку' is used in the dative case to indicate the recipient of the action.
Я подарил подарок внуку.
I gave a gift to my grandson.
In this sentence, 'внуку' is again in the dative case, describing the person to whom the story was told.
Сказка, рассказанная внуку, была интересной.
The story told to the grandson was interesting.
The dative case 'внуку' is employed to specify the individual receiving the regards.