why

[hwahy, wahy]

adverb

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

   Why did you behave so badly?

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

/ 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

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.

Word History and Origins

Origin of why¹

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

Word History and Origins

Origin of why¹

Old English hwī; related to Old Norse hvī, Gothic hveileiks what kind of, Latin quī

Example Sentences

"If they're going to grant more power to the executive its going to have to explain why."

From BBC

Los Angeles County is refusing to disclose a preliminary report that could explain why officials suggested that the downtown skyscraper it recently purchased to serve as its new headquarters should receive a seismic retrofit.

From Los Angeles Times

That could be one reason why the stock market has appeared largely unfazed by the current stand-off.

From BBC

It did not explain why only 10 had arrived.

From BBC

But before we confront the gender elephant in the room, it’s necessary to explore why Greene is actually doing a lot of smart things.

From Salon