Apr 4, 2026 · The meaning of WHY is for what cause, reason, or purpose. How to use why in a sentence. When we ask for reasons in speaking, we can use the phrase why is that? In informal conversations we often say why’s that?: … You use why in questions when you ask about the reasons for something. Why hasn't he brought the bill? Why didn't he stop me? Why can't I remember the exact year we married? for what reason, purpose, or cause?: why are you here?. (used in indirect questions): tell me why you're here. Explore the history, meaning, and necessity of the question that drives discovery from toddlers to theoretical physicists. why, adv., int., & n. meanings, etymology, pronunciation and more in the Oxford English Dictionary Definition of WHY in the Definitions.net dictionary. Information and translations of WHY in the most comprehensive dictionary definitions resource on the web.