US: /ˈθiɝi/, /ˈθɪɹi/
UK: /θˈi‍əɹi/

English Vietnamese dictionary

theory /'θiəri/
  • danh từ
    • thuyết, học thuyết
      • Darwin's theory of evolution: thuyết tiến hoá của Đác-uyn
    • thuyết riêng
      • there's a theory that the lung cancer is caused by cigarettes: có thuyết cho là bệnh ung thư phổi do thuốc lá gây nên
    • lý thuyết, lý luận, nguyên lý
      • good in theory but inapplicable in practice: hay về lý thuyết nhưng không áp dụng được trong thực hành

Advanced English dictionary

+ noun (plural theories)
1 [C, U] a formal set of ideas that is intended to explain why sth happens or exists: According to the theory of relativity, nothing can travel faster than light. + The debate is centred around two conflicting theories.
2 [U] the principles on which a particular subject is based: the theory and practice of language teaching + literary / political theory
3 [C] ~ (that) an opinion or idea that sb believes is true but that is not proved: I have this theory that most people prefer being at work to being at home.
Idioms: in theory used to say that a particular statement is supposed to be true but may in fact be wrong: In theory, these machines should last for ten years or more. + That sounds fine in theory, but have you really thought it through? + 'Aren't you supposed to be retired?' 'Yes, in theory.'

Collocation dictionary


complete | partial | general
Einstein's general theory of relativity
| coherent | unified
the existence of a grand unified theory that determines everything in the universe
| current, new | classical
the classical theory of gravity
| pet
One of her pet theories is that people who restrict their calorie intake live longer.
| conflicting | critical | abstract
His comments are just abstract theory and show little understanding of the realities of the situation.
| economic, legal, linguistic, literary, political, scientific, social, etc. | post-modernist, structuralist, etc.
Current feminist theory consists of several different trends.
| conspiracy
a conspiracy theory about the princess's death
| chaos, game, quantum, number, particle, probability, relativity, etc.


Each school has its own set of theories.


have, hold | advance, develop, formulate, produce, propose | work on
Police are working on the theory that the murderer was known to the family.
| refute | confirm, prove | disprove | challenge, test


evolve | hold sth, suggest sth


in ~
In theory, these machines should last for ten years.
| ~ about
He has a theory about why dogs walk round in circles before going to sleep.


theory and practice
the distinction/relationship between theory and practice

Concise English dictionary

theories'θɪːrɪ /'θɪərɪ
+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
+a tentative theory about the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena
+a belief that can guide behavior