why

Etymology

It is inherited from Middle English whi,^[2][3][4] inherited from Old English hwȳ, also hwī,^[5][6][3] the instrumental case of hwæt (“what”), showing for what purpose or by what means, used as an adverb,^[3][2][4] from Proto-Germanic *hwī.^[2][3] It goes back to Proto-Indo-European *kwei, the locative of the interrogative stem *kwo-,^[3][7][2][8] the source also of what and who.^[7][9] It is cognate with Old Saxon hwī, Old Norse hví and Danish hvi,^[9][3] and further with Ancient Greek πεῖ (peî, “where”)^[2][3][10] and Latin quī.^[8][11] Ayto notes that the word has died out in all the Germanic languages except Danish and English,^[7] although the OED also records Swedish vi.^[9]

Earliest recorded meaning

For what reason, in an indirect question: before 899, in King Alfred's translation of Boethius.^[9][3] His translation of Gregory's Pastoral Care already has the direct question that implies a protest or a denial.^[9]

Semantic evolution

Old English already used why for "on account of which", now almost always after reason.^[9] Johnson (1755) separated the interrogative "for what reason?" from the relative "for which reason".^[12] A clause with why as subject or predicate, "the reason for which", is recorded from about 1475.^[9] The word had become a noun by about 1300, first for a cause or reason;^[2][3][4] Johnson quotes Shakespeare's "Every why hath a wherefore".^[12] As an exclamation it was already expressing surprise in Old English according to the revised OED, and before 1350 it was calling attention to a statement, against a possible doubt;^[9] Barnhart and Merriam-Webster date the interjection only from 1519,^[3][5] Etymonline from the mid-14th century.^[2] In Shakespeare it could be an impatient summons.^[9] Why don't I...?, a positive suggestion, dates from 1685,^[9] and why aye, emphatic agreement, from 1638.^[9] In many English dialects the word was used redundantly at the opening of a sentence, in forms such as wey, whoy and wya.^[13]

Timeline

• before 899 – adverb, for what reason, in an indirect question.^[9][3]
• Old English – in a direct question; relative, on account of which; exclamation of surprise.^[9]
• c. 1200 – the form whi, in the Ormulum.^[3]
• c. 1300 – noun, cause, reason.^[2][3]
• before 1350 – exclamation calling attention to the following statement, in King Horn.^[9] Barnhart and Merriam-Webster date the interjection to 1519.^[3][5]
• c. 1475 – the reason for which, introducing a clause.^[9]
• 1599 – impatient summons, in Romeo and Juliet (obsolete).^[9]
• 1638 – why aye, yes indeed.^[9]
• 1685 – why don't I...?, a positive suggestion.^[9][10]
• 1874 – verb, to ask the question "why?".^[9]

Meanings

Adverb

1. For what reason, cause or purpose, in direct and indirect questions: Why did the train stop? I asked why the shop had closed.^[14][5][9]
2. Used to imply that there is no good reason for something: Why should I apologise?^[9]
3. why don't...?: used to make a suggestion: Why don't we walk?^[9][10]

Conjunction

1. On account of which; for which, mostly after reason: I can see no reason why she should pay.^[14][5][9]
2. The reason for which: That is why I left.^[9][10]

Noun

1. The reason or cause of something, often in the plural: the whys and wherefores.^[14][5][10]
2. A puzzling question; a problem or enigma.^[5][10]

Interjection

1. Expressing surprise, disagreement or protest: Why, you've cut your hair!^[14][9]
2. Marking a pause or calling attention to what follows: If it rains, why, we'll stay indoors.^[5][9]

Word family

• forwhy

Related words

• what
• who

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ a b c d e f g h i j k l m n Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
4. ^ a b c Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
5. ^ a b c d e f g h Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
6. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
7. ^ a b c Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
8. ^ a b Orel, Vladimir (2003), A Handbook of Germanic Etymology, Leiden / Boston: Brill
9. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
10. ^ a b c d e f Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
11. ^ Holthausen, Ferdinand (1934), Altenglisches etymologisches Wörterbuch, Heidelberg: Carl Winter
12. ^ a b Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
13. ^ Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)
14. ^ a b c d Collins English Dictionary (2023), Glasgow: HarperCollins