An expression in the usage of a language that is peculiar to itself either in having a meaning that cannot be derived from the conjoined meanings of its elements or in its grammatically atypical use of words.
Idiom:
pick up a radio wave etc.
Meaning:
to catch or receive the sound of a radio etc.
Example:
We could not pick up any radio stations when we were travelling through the mountains.
List of common idioms, their meanings and examples of their usage in sentences
Idioms can be a powerful linguistic tool only when they are used in the right way in the right places.