This is the 261st most frequent Icelandic word.
hverjum
"Hverjum" means "whom" or "to whom" in English, in the dative case.
In this sentence, 'hverjum' is the dative singular form of 'hver', used to indicate the indirect object receiving the action.
Hún gefur gjöf hverjum vini sínum á afmælisdaginn.
She gives a gift to each of her friends on her birthday.
Here, 'hverjum' functions as the dative singular form of 'hver', describing the location in dative case.
Í hverjum stað sem við heimsækjum, lærum við eitthvað nýtt.
In every place we visit, we learn something new.
In this case, 'hverjum' is the dative singular form of 'hver', used to describe the person receiving the help.