Definition of 'theory'
Word forms: plural theories
2. countable noun
3. uncountable noun
The theory of a practical subject or skill is the set of rules and principles that form the basis of it.
[Also + of]4.
See in theory
Collins COBUILD Advanced Learner’s Dictionary. Copyright © HarperCollins Publishers
British English pronunciation
American English pronunciation
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Word Frequency
theory in British English
nounWord forms: plural -ries
1.
a system of rules, procedures, and assumptions used to produce a result
4.
5.
a set of hypotheses related by logical or mathematical arguments to explain and predict a wide variety of connected phenomena in general terms
the theory of relativity
6. a nontechnical name for hypothesis (sense 1)
Collins English Dictionary. Copyright © HarperCollins Publishers
Word origin
C16: from Late Latin theōria, from Greek: a sight, from theōrein to gaze upon
Word Frequency
theory in American English
nounWord forms: plural ˈtheories
SYNONYMY NOTE: theory, as compared here, implies considerable evidence in support of a formulated general
principle explaining the operation of certain phenomena [the theory of evolution]; hypothesis implies an inadequacy of evidence in support of an explanation that is tentatively
inferred, often as a basis for further experimentation [the nebular hypothesis]; law implies an exact formulation of the principle operating in a sequence of events in
nature, observed to occur with unvarying uniformity under the same conditions [the law of the conservation of energy]2.
a speculative idea or plan as to how something might be done
4.
a formulation of apparent relationships or underlying principles of certain observed phenomena which has been verified to some degree
5.
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
Houghton Mifflin Harcourt. All rights reserved.
Word origin
< Fr or LL: Fr théorie < LL theoria < Gr theōria, a looking at, contemplation, speculation, theory < theōrein: see theoremWord Frequency
theory in American English
(ˈθiəri, ˈθɪəri)
nounWord forms: plural -ries
SYNONYMS 1. theory, hypothesis are used in non-technical contexts to mean an untested idea or opinion. A theory in technical use is a more or less verified or established explanation accounting
for known facts or phenomena: the theory of relativity. A hypothesis is a conjecture put forth as a possible explanation of phenomena or relations, which
serves as a basis of argument or experimentation to reach the truth: This idea is only a hypothesis. 1.
Einstein's theory of relativity
2.
4.
the branch of a science or art that deals with its principles or methods, as distinguished from its practice
music theory
5.
a particular conception or view of something to be done or of the method of doing it; a system of rules or
principles
6.
contemplation or speculation
7.
guess or conjecture
Most material © 2005, 1997, 1991 by Penguin Random House LLC. Modified entries © 2019
by Penguin Random House LLC and HarperCollins Publishers Ltd
Word origin
[1590–1600; ‹ LL theōria ‹ Gk theōría a viewing, contemplating, equiv. to theōr(eîn) to view + -ia -y3]Examples of 'theory' in a sentence
theory
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In other languages
theory
British English: theory
/ˈθɪərɪ/ NOUN
A theory is a formal idea or set of ideas intended to explain something.
...the theory of evolution.
- American English: theory /ˈθɪəri/
- Arabic: نَظَرِيَّة
- Brazilian Portuguese: teoria
- Chinese: 理论
- Croatian: teorija
- Czech: teorie
- Danish: teori
- Dutch: theorie
- European Spanish: teoría
- Finnish: teoria
- French: théorie
- German: Theorie
- Greek: θεωρία
- Italian: teoria
- Japanese: 理論
- Korean: 이론
- Norwegian: teori
- Polish: teoria
- European Portuguese: teoria
- Romanian: teorie
- Russian: теория
- Latin American Spanish: teoría
- Swedish: teori
- Thai: ทฤษฎี
- Turkish: kuram
- Ukrainian: теорія
- Vietnamese: lý thuyết
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Definition of theory from the Collins English Dictionary
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