This is the 62nd most frequent French word.
ça
"Ça" means "that" or "it" in English.
'Ça' is used here as a pronoun referring to the general state or situation, acting as the subject of the sentence.
Ça va bien.
It's going well.
'Ça' functions here as a pronoun referring to an unspecified or previously mentioned thing.
Qu'est-ce que ça signifie?
What does that mean?
'Ça' is used demonstratively here to refer to a specific thing or action that is being pointed out or is in focus.