What does “theory” mean?
- 1
nouna set of ideas that tries to explain why something happens
Darwin’s theory of evolution changed science.
- 2
nounan idea someone believes may be true but cannot prove
My theory is that the cat broke the vase.
Theory at a glance
- Part of speech
- noun
- CEFR level
- B1 (intermediate)
- Pronunciation
- /ˈθiəri/ · THEE-uh-ree
- Forms
- theories
How to use “theory” correctly
“In theory” means something should work but may not in real life: “In theory it’s easy; in practice it’s hard.”
Common phrases with “theory”
- in theory
- a theory of sth
- conspiracy theory
- test a theory
Synonyms, opposites and related words
Antonyms (opposite meaning)
Word family
- theoretical
- theoretically
- theorist
- theorize
“theory” is on these word lists
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