Definition, CEFR level B1, pronunciation, examples, and quiz.
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Definition
nounA description of an event or system that is considered to be accurate.
nounA coherent statement or set of ideas that explains observed facts or phenomena and correctly predicts new facts or phenomena not previously observed, or which sets out the laws and principles of something known or observed; a hypothesis confirmed by observation, experiment etc.
Sentence Examples
I think I have a theory about that.
In theory, there is no difference between theory and practice. But, in practice, there is.
Darwin's ____ of evolution explains how species change over time.
CEFR Practice Quiz (Alternate)
Einstein's ____ of relativity transformed our understanding of the universe and the nature of time today.
Word Origin & History
Etymology tree
Proto-Hellenic *tʰáwā
Ancient Greek θέᾱ (théā)
Proto-Indo-European *wer-der.
Proto-Indo-European *h₃ekʷ-der.
Proto-Indo-European *weyd-der.
Ancient Greek ὁράω (horáō)
Ancient Greek *θεᾱ-(ϝ)ορός, *θεη-(ϝ)ορός (*theā-(w)orós, *theē-(w)orós)
Ancient Greek θεωρός (theōrós)
Proto-Indo-European *-h₂
Proto-Indo-European *-éh₂
Proto-Indo-European *-i-eh₂
Proto-Hellenic *-íā
Ancient Greek -ῐ́ᾱ (-ĭ́ā)
Ancient Greek θεωρία (theōría)bor.
Late Latin theōrialbor.
Middle French théoriebor.
English theory
Borrowed from Middle French théorie, a learned borrowing from Late Latin theōria, borrowed from Ancient Greek θεωρία (theōría), from θεωρός (theōrós, “spectator”) + -ῐ́ᾱ (-ĭ́ā).
Literary Quotations & Historical Citations
"As they encrease the hatred of vice in some, so doe they enlarge the theory of wickednesse in all."
— 1646, Thomas Browne, Pseudodoxia Epidemica, VII.19:
"Does this mean, then, that there can be no such thing as a theory of literature?"
— 1990, Tony Bennett, Outside Literature, page 139:
"It was only when Einstein's theory of relativity was published in 1915 that physicists could show that Mercury's "anomaly" was actually because Newton's gravitational theory was incomplete."
— 2002 May 23, Duncan Steel, The Guardian:
"The world would need additional decades [...] before the Big Bang would begin to move from interesting idea to established theory."
— 2003, Bill Bryson, A Short History of Nearly Everything, BCA, page 118:
"Scientists and creationists are understanding the word "theory" in two very different senses. Evolution is a theory in the same sense as the heliocentric theory. In neither case should the word "only" be used, as in "only a theory"."
— 2009, Richard Dawkins, The Greatest Show On Earth: The Evidence for Evolution, Bantam, page 10: