theory
gb/θˈiɚi/ us/θˈiɚi/
B1
英語
~ 700
語義
0件の語義
名詞
B2
entity
1
Explanation supported by evidence
An idea that explains why things happen, based on facts and study.
用法パターン：
a theory about [something]
よくある間違い：
Learners sometimes confuse 'theory' with 'hypothesis'. A hypothesis is an idea to be tested; a theory is already supported by evidence.
類義語
explanation (More general; can be for everyday situations, not just formal or scientific contexts.)
対義語
fact (A fact is something known to be true without the need for explanation or hypothesis.)
コロケーション
scientific theory
|develop a theory
|theory suggests
|test a theory
|propose a theory
テーマ
science
|education
|research
|core_vocabulary
例文
- Einstein's theory of relativity changed our understanding of space and time.
- The theory explains how galaxies form.
- Her theory is that the missing money was stolen by someone inside the company.
- The researchers developed a new theory to explain the results.
- According to current theory, the universe began with the Big Bang.
学習者向け例文
- I read about a new theory in science class.
- Her theory is that plants grow faster in sunlight.
- The theory says the earth goes around the sun.
- Scientists have a theory about why animals migrate.
名詞
B2
entity
2
General ideas or principles
An idea or set of rules about how something works or should work.
用法パターン：
theory of [something]
よくある間違い：
Learners sometimes use 'in theory' incorrectly to mean 'probably' instead of 'according to the plan or idea'.
類義語
principle (Refers to a basic truth or rule; may be more fixed than 'theory'.)
対義語
practice (Refers to the actual doing of something, as opposed to the ideas about it.)
コロケーション
political theory
|economic theory
|management theory
|in theory
テーマ
philosophy
|education
|work
|core_vocabulary
例文
- In theory, this plan should save the company money.
- She studies political theory at university.
- The new economic theory challenges traditional views.
- According to game theory, players act in their own interest.
学習者向け例文
- In theory, the train should arrive at 8.
- We learned about economic theory in class.
- His theory is that people are happier in small towns.
名詞
B1
entity
3
Unproven belief or guess
A guess or idea that might explain something, but is not certain.
用法パターン：
have a theory that [clause]
よくある間違い：
Learners may overuse 'theory' for casual guesses; 'idea' or 'guess' can be more natural in informal speech.
類義語
speculation (More formal; often suggests guessing without strong evidence.)
対義語
certainty (Something known for sure, without doubt.)
コロケーション
have a theory
|my theory is that
|conspiracy theory
テーマ
daily life
|communication
|core_vocabulary
例文
- I have a theory that my neighbor is avoiding me.
- Her theory is that the cat goes out at night to hunt.
- There's a popular conspiracy theory about that event.
学習者向け例文
- I have a theory that it will rain today.
- His theory is that she is tired.
- They talk about a strange conspiracy theory.
文法
辞書形
theory
IPA
GB/θˈiɚi/
US/θˈiɚi/
音節・強勢
the - ory （2音節）
Stress on 1st syllable (the)
活用形
Noun
- Base: theory
- Plural: theories, theory
関連語
Forms
theories
noun
Core family
theoretical
adjective B2
theoretically
adverb B2
表現
conspiracy theory
1/kənspˈɪɹəsi θˈiɚi/
fixed phrase
belief about secret harmful plot
An explanation of an event that says a secret group planned it for a bad reason, usually without good proof.
例文
- Some people believe the moon landing was a conspiracy theory.
- The internet has made it easier for conspiracy theory videos to reach millions of people.
- The internet has made it easier for conspiracy theories to spread.
- He dismissed the idea that the vaccine is a government plot as a wild conspiracy theory.
- Some conspiracy theory communities moved to new platforms after being banned.
in theory
1/ˈɪn θˈiɚi/
fixed phrase
According to ideas or plans
When something should happen based on ideas or plans, but it might not happen in real life.
例文
- In theory, this method should work every time.
- In theory, the plan should work perfectly.
- In theory, anyone can apply for the job, but few are qualified.
- In theory, anyone can apply for the job, but in practice it’s very competitive.
in theory
2/ˈɪn θˈiɚi/
fixed phrase
according to theory, not practice
According to ideas or rules of how something should work, not necessarily how it really works.
例文
- In theory, the new law will reduce traffic, but many people doubt it.
- The plan sounds perfect in theory, but it will be hard to carry out.
- In theory, children learn faster with smaller classes.