why

American  

[hwahy, wahy] / ʰwaɪ, waɪ /

adverb

1. for what? for what reason, cause, or purpose?.

   Why did you behave so badly?

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conjunction

1. for what cause or reason.

   I don't know why he is leaving.

2. for which; on account of which (usually after reason to introduce a relative clause).

   the reason why he refused to go.

3. the reason for which.

   That is why he returned.

noun

plural

whys

1. a question concerning the cause or reason for which something is done, achieved, etc..

   a child's unending hows and whys.

2. the cause or reason.

   the whys and wherefores of a troublesome situation.

interjection

1. (used as an expression of surprise, hesitation, etc., or sometimes a mere expletive).

   Why, it's all gone!

why British  

/ waɪ /

adverb

1. 1. for what reason, purpose, or cause?

      why are you here?

   2. ( used in indirect questions )

      tell me why you're here

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pronoun

1. for or because of which

   there is no reason why he shouldn't come

noun

1. (usually plural) the reason, purpose, or cause of something (esp in the phrase the whys and wherefores )

interjection

1. an introductory expression of surprise, disagreement, indignation, etc

   why, don't be silly!

Usage

See reason.

Etymology

Origin of why

First recorded before 900; Middle English; Old English hwī, hwȳ, instrumental case of hwæt what; cognate with Old Norse hvī

Example Sentences

We asked NEM why they had posted the AI video and whether they had made it, but they did not comment.

From BBC • Apr. 4, 2026

In response to the reader last week who was wondering why so many All-Area basketball players are leaving L.A. for other colleges: Mick Cronin.

From Los Angeles Times • Apr. 4, 2026

But if her firing says anything, it may be less about why she lost the job — and more about how quickly the trappings of power can vanish once she did.

From Salon • Apr. 4, 2026

"Understanding that larger circuit could help answer a simple question of why someone with an anxiety disorder might exhibit inappropriate fear responses to something that isn't actually dangerous," Halladay said.

From Science Daily • Apr. 4, 2026

It felt safe there, relaxed, and I want to feel that again, and I can’t help wondering why I’ve not felt that way when Rhys holds me.

From "Red Flags and Butterflies" by Sheryl Azzam