This is the 6383rd most frequent Catalan word.
of
The Catalan word "of" does not exist. You may mean "of" in English or a different Catalan word like "ofici" (trade/occupation).
Here, 'de' is used to indicate possession or source.
El llibre de la biblioteca és molt interessant.
The book from the library is very interesting.
In this case, 'de' denotes relationship or association between terms.
El color de la samarreta és blau.
The color of the shirt is blue.
Here, 'de' specifies the event or occasion tied to the noun.