This is the 8105th most frequent Catalan word.
creus
"Creus" means "crosses" (plural form of "creu") or "you believe" (second-person singular of "creure").
In this sentence, 'creus' means 'crosses', and it is the plural noun form referring to objects with a cross shape.
Al museu hi havia creus antigues.
In the museum, there were old crosses.
Here, 'creus' is the conjugated form of the verb 'creure' (to believe) for the second person singular in present tense, used to ask if the listener believes in something.
Creus que això és veritat?
Do you believe this is true?
In this example, there seems to be a typo. The correct usage would be 'creu' (without 's'), aligning with singular agreement to 'una persona' (one person).