theory
♦♦ theo|ry /θ'ɪəri/ (theories)
1 [N-VAR] usu with supp
A theory is a formal idea or set of ideas that is intended to explain something.
Einstein formulated the Theory of Relativity in 1905.
2 [N-COUNT]
If you have a theory about something, you have your own opinion about it which you cannot prove but which you think is true.
There was a theory that he wanted to marry her...
3 [N-UNCOUNT] usu with supp, supp N, N of n
The theory of a practical subject or skill is the set of rules and principles that form the basis of it.
He taught us music theory.
4 [PHRASE] PHR with cl
You use in theory to say that although something is supposed to be true or to happen in the way stated, it may not in fact be true or happen in that way.
A school dental service exists in theory, but in practice, there are few dentists to work in them.
= theoreticallybig bang theo|ry
[N-SING] the N
In astronomy the big bang theory is a theory that suggests that the universe was created as a result of an extremely large explosion.con|spira|cy theo|ry (conspiracy theories)
[N-COUNT]
A conspiracy theory is a belief that a group of people are secretly trying to harm someone or achieve something. You usually use this term to suggest that you think this is unlikely.
Did you ever swallow the conspiracy theory about Kennedy?
1 [N-VAR] usu with supp
A theory is a formal idea or set of ideas that is intended to explain something.
Einstein formulated the Theory of Relativity in 1905.
2 [N-COUNT]
If you have a theory about something, you have your own opinion about it which you cannot prove but which you think is true.
There was a theory that he wanted to marry her...
3 [N-UNCOUNT] usu with supp, supp N, N of n
The theory of a practical subject or skill is the set of rules and principles that form the basis of it.
He taught us music theory.
4 [PHRASE] PHR with cl
You use in theory to say that although something is supposed to be true or to happen in the way stated, it may not in fact be true or happen in that way.
A school dental service exists in theory, but in practice, there are few dentists to work in them.
= theoreticallybig bang theo|ry
[N-SING] the N
In astronomy the big bang theory is a theory that suggests that the universe was created as a result of an extremely large explosion.con|spira|cy theo|ry (conspiracy theories)
[N-COUNT]
A conspiracy theory is a belief that a group of people are secretly trying to harm someone or achieve something. You usually use this term to suggest that you think this is unlikely.
Did you ever swallow the conspiracy theory about Kennedy?