Meaning of Why
Bangla: কেন, কি জন্য, কি কারণে, কিসে
Adverb / ক্রিয়া বিশেষণ / क्रिया-विशेषण
for what? for what reason, cause, or purpose?: Why did you behave so badly?
for what cause or reason: I don't know why he is leaving.
for which; on account of which (usually after reason to introduce a relative clause): the reason why he refused to go.
the reason for which: That is why he returned.
a question concerning the cause or reason for which something is done, achieved, etc.: a child's unending hows and whys.