theory

Pronunciation

• IPA: UK /ˈθɪə.ri/, US /ˈθiː.ə.ri/^[1]

Etymology

It is borrowed from Late Latin theōria,^[2][3][4] used by Jerome,^[2] from Ancient Greek θεωρία (theōría, “contemplation, speculation; a looking at; a sight, spectacle”),^[2][3][5] from θεωρεῖν (theōreîn, “to look at, consider, speculate”),^[2][3] from θεωρός (theōrós, “spectator”),^[2][6] from θέα (théa, “a view”), the source of theater, and ὁρᾶν (horân, “to see”),^[2][3] perhaps from Proto-Indo-European *wer- (“to perceive”), according to Watkins.^[2] Philosophy credits the development of the Greek word's sense to Pythagoras.^[2]

Earliest recorded meaning

A conception or mental scheme of something to be done, or of the way to do it: 1592 in Merriam-Webster,^[4] 1597 in the OED, in Hooker's Ecclesiastical Polity,^[7][3] and the 1590s in Etymonline.^[2]

Semantic evolution

In the early 17th century the word also meant a sight or spectacle (1605) and mental view, contemplation, both now obsolete.^[7] The principles or methods of a science or art, as against its practice, is from 1613, in Cawdrey's Table Alphabeticall,^[3][7] as in music theory.^[2] A system of ideas held as an explanation of a group of facts is from 1638,^[7] and a systematic statement of the principles of a branch of mathematics from 1799.^[7] The loose sense, “a hypothesis, a mere conjecture”, is from 1792.^[7] In theory, as opposed to in practice, follows from the sense of abstract knowledge (1624).^[7][8] Theorist is from the 16th century and theorize from the 17th.^[6]

Timeline

• 1592 – a mental scheme.^[4]
• 1605 – a sight, spectacle.^[7]
• 1613 – the principles of a science or art.^[3][7]
• 1638 – an explanatory system of ideas.^[7]
• 1792 – a hypothesis, conjecture.^[7]
• 1799 – the principles of a branch of mathematics.^[7]

Modern meaning

Noun

1. A set of statements or principles that explains a group of facts or phenomena, especially one that has been tested and can be used to predict.
2. The principles of an art or science, as distinct from its practice: music theory.
3. Abstract reasoning; speculation.
4. An assumption or hypothesis; a guess.
5. In mathematics, a body of theorems on a subject: number theory.

Word family

• theorist

Related words

• theorem
• theoretical
• theorise
• theorize
• theater

Usage notes

In science a theory is a well-tested explanation, while in ordinary use the word often means a mere guess.^[8][7] A separate theory, in Greek history a group of envoys sent by a state to perform a religious rite, is from 1842.^[7][9]

References

1. ^ Jones, Daniel (2011), Cambridge English Pronouncing Dictionary, 18th ed., ed. Peter Roach, Jane Setter and John Esling, Cambridge: Cambridge University Press
2. ^ a b c d e f g h i j Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
4. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
6. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
7. ^ a b c d e f g h i j k l m n Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
8. ^ a b The American Heritage Dictionary of the English Language (1992), 3rd ed., Boston: Houghton Mifflin
9. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press