This is the 110th most frequent Dutch word.
zei
"Zei" means "said."
In this sentence, "zei" is the past tense of the verb "zeggen", meaning "to say" or "to tell".
"Hij zei dat hij morgen zou komen."
"He said that he would come tomorrow."
Here, "zei" is used in a question form to ask if someone stated something, again as the past tense of "zeggen".
"Zei je iets? Ik hoorde het niet duidelijk."
"Did you say something? I didn't hear it clearly."
In this context, "zei" emphasizes the act of having said something in the past to validate a statement or outcome.