adverb
Definition: This word is used to ask about the reason or purpose of something.
Example: Why did you choose that book to read?
conjunction
Definition: A word used to ask for the reason or purpose of something.
Example: I don't understand why you did that.
interjection
Definition: This word is used to ask for the reason or explanation for something. It can also express surprise or impatience.
Example: Why did you choose that restaurant for dinner?
noun
Definition: The reason or explanation for something, often used to ask about the cause of an action or situation.
Example: She asked him the why behind his decision to move.