English tips! idioms & idiomatic expressions

An idiom is a combination of words that has a meaning that is different from the meanings of the individual words themselves. It can have a literal meaning in one situation and a different idiomatic meaning in another situation. It is a phrase which does not always follow the normal rules of meaning and grammar.
To sit on the fence can literally mean that one is sitting on a fence.
I sat on the fence and watched the game.
However, the idiomatic meaning of to sit on the fence is to not clearly choose a side regarding some issue.
The politician sat on the fence and would not clearly state his opinion about the tax issue.

Many English idioms are similar to expressions in other languages and can be easy for a learner to understand. Other idioms come from older phrases which have changed over time.

Other idioms come from such things as sports and may require some special cultural knowledge to understand them.

Most idioms are fixed in their grammatical structure. The expression to sit on the fence cannot become to sit on a fence or to sit on the fences.