a coherent group of general propositions used as principles of explanation for a class of phenomena: Einstein's theory of relativity.
2.
a proposed explanation whose status is still conjectural, in contrast to well-established propositions that are regarded as reporting matters of actual fact.
3.
Mathematics. a body of principles, theorems, or the like, belonging to one subject: number theory.
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.
[Origin: 1590–1600; < LL theōria < Gk theōría a viewing, contemplating, equiv. to theōr(eǐn) to view + -ia-y3]
—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.
A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.
The branch of a science or art consisting of its explanatory statements, accepted principles, and methods of analysis, as opposed to practice: a fine musician who had never studied theory.
A set of theorems that constitute a systematic view of a branch of mathematics.
Abstract reasoning; speculation: a decision based on experience rather than theory.
A belief or principle that guides action or assists comprehension or judgment: staked out the house on the theory that criminals usually return to the scene of the crime.
An assumption based on limited information or knowledge; a conjecture.
[Late Latin theōria, from Greek theōriā, from theōros, spectator : probably theā, a viewing + -oros, seeing (from horān, to see).]
1592, "conception, mental scheme," from L.L. theoria (Jerome), from Gk. theoria "contemplation, speculation, a looking at, things looked at," from theorein "to consider, speculate, look at," from theoros "spectator," from thea "a view" + horan "to see." Sense of "principles or methods of a science or art (rather than its practice)" is first recorded 1613. That of "an explanation based on observation and reasoning" is from 1638. The verb theorize is recorded from 1638.
a well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena; "theories can incorporate facts and laws and tested hypotheses"; "true in fact and theory"
2.
a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena; "a scientific hypothesis that survives experimental testing becomes a scientific theory"; "he proposed a fresh theory of alkalis that later was accepted in chemical practices" [syn: hypothesis]
3.
a belief that can guide behavior; "the architect has a theory that more is less"; "they killed him on the theory that dead men tell no tales"
an idea or explanation which has not yet been proved to be correct Example: There are many theories about the origin of life; In theory, I agree with you, but it would not work in practice.
Arabic:
نَظَرِيَّه
Chinese (Simplified):
意见，观念
Chinese (Traditional):
意見，觀念
Czech:
teorie
Danish:
teori
Dutch:
theorie
Estonian:
oletus, teooria
Finnish:
teoria
French:
théorie
German:
die Theorie
Greek:
θεωρία
Hungarian:
elmélet
Icelandic:
kenning
Indonesian:
teori
Italian:
teoria
Japanese:
理論
Latvian:
teorija
Lithuanian:
teorija
Norwegian:
teori, lære
Polish:
teoria
Portuguese (Brazil):
teoria
Portuguese (Portugal):
teoria
Romanian:
teorie
Russian:
теория
Slovak:
teória
Slovenian:
teorija
Spanish:
teoría
Swedish:
teori
Turkish:
kuram, teori
theory2[ˈθiəri]noun
the main principles and ideas in an art, science etc as opposed to the practice of actually doing it Example: A musician has to study both the theory and practice of music.
theoryAudio Help (thē'ə-rē, thîr'ē) Pronunciation Key
A set of statements or principles devised to explain a group of facts or phenomena. Most theories that are accepted by scientists have been repeatedly tested by experiments and can be used to make predictions about natural phenomena. See Note at hypothesis.
In science, an explanation or model that covers a substantial group of occurrences in nature and has been confirmed by a substantial number of experiments and observations. A theory is more general and better verified than a hypothesis. (SeeBig Bang theory, evolution, andrelativity.)
theory The consensus, idea, plan, story, or set of rules that is currently being used to inform a behaviour. This usage is a generalisation and (deliberate) abuse of the technical meaning. "What's the theory on fixing this TECO loss?" "What's the theory on dinner tonight?" ("Chinatown, I guess.") "What's the current theory on letting lusers on during the day?" "The theory behind this change is to fix the following well-known screw...." (1994-12-14)
Hy*poth"e*sis\, n.; pl. Hypotheses. [NL., fr. Gr. ? foundation, supposition, fr. ? to place under, ? under + ? to put. See Hypo-, Thesis.]1. A supposition; a proposition or principle which is supposed or taken for granted, in order to draw a conclusion or inference for proof of the point in question; something not proved, but assumed for the purpose of argument, or to account for a fact or an occurrence; as, the hypothesis that head winds detain an overdue steamer. An hypothesis being a mere supposition, there are no other limits to hypotheses than those of the human imagination. --J. S. Mill. 2. (Natural Science) A tentative theory or supposition provisionally adopted to explain certain facts, and to guide in the investigation of others; hence, frequently called a working hypothesis. Syn: Supposition; assumption. See Theory. Nebular hypothesis. See under Nebular.
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Audio Help [thee-uh-ree, theer-ee] Pronunciation Key 
