This is the 876th most frequent Croatian word.
svjetska
"Svjetska" means "world" or "global" in English.
Here, 'svjetska' modifies 'prvenstva', specifying that these championships are of a global scale or involve international participants.
Ona je osvojila svjetska prvenstva u plivanju.
She has won the world championships in swimming.
In this sentence, 'svjetska' is used as an adjective describing the scope or nature of the conference, implying it is of worldwide relevance.
Održava se svjetska konferencija o klimatskim promjenama.
A global conference on climate change is taking place.
In this case, 'svjetska' qualifies 'ekonomija', indicating that the subject pertains to the world as a whole.