This is the 463rd most frequent Croatian word.
naših
"Naših" means "of ours" or "our" (genitive plural form).
The possessive pronoun 'naših' is used as a genitive plural form to specify possession pertaining to 'we/us' relating to 'best friends'.
Ovo je jedna od naših najboljih prijateljica.
This is one of our best friends.
Here, 'naših' in genitive plural specifies possession ('of our') regarding 'relatives'.
Prisustvovala sam vjenčanju naših rođaka.
I attended the wedding of our relatives.
In this sentence, 'naših' complements the genitive plural form to relate 'memories' to 'our'.