This is the 3199th most frequent Catalan word.
relatives
"Relatives" in Catalan means "family members" or "people related by blood or marriage."
In this sentence, 'relatius' is used as an adjective meaning 'related' or 'pertaining to', modifying the noun 'documents'.
Els documents relatius a la investigació estan a l'arxiu.
The documents related to the investigation are in the archive.
Here, 'relatives' functions as an adjective describing 'opinions', conveying the meaning 'related to'.
Les seves opinions relatives al tema varen ser interesants.
Their opinions relative to the subject were interesting.
'Relatius' serves as an adjective in this sentence, referring to 'books' in the context of discussing their relationship to 'history'.