This is the 1859th most frequent Polish word.
jaka
"Jaka" means "what" or "which" (feminine singular form).
In this question, "jaka" is used as an interrogative pronoun asking about the characteristics or type of something.
Jaka jest dzisiaj pogoda?
What is the weather today?
Here, "jaka" is used to inquire about the specific nature or details of a decision.
Nie wiesz, jaka decyzja została podjęta?
Do you not know what decision was made?
In this sentence, "jaka" introduces a clause describing the qualities or specifics of the mentioned difference.