Meaning of THEORY in English
Frequency: The word is one of the 1500 most common words in English.
A ~ is a formal idea or set of ideas that is intended to explain something.
Einstein formulated the Theory of Relativity in 1905.
N-VAR: usu with supp
If you have a ~ about something, you have your own opinion about it which you cannot prove but which you think is true.
There was a ~ that he wanted to marry her...
The ~ of a practical subject or skill is the set of rules and principles that form the basis of it.
He taught us music ~.
N-UNCOUNT: usu with supp, supp N, N of n
You use in ~ 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 ~, but in practice, there are few dentists to work in them.
PHRASE: PHR with cl
Collins COBUILD. Толковый словарь английского языка для изучающих язык Коллинз COBUILD (международная база данных языков Бирмингемского университета) . 2012