Idioms
A group of words which have a different meaning when used together from the one they would have if you took the meaning of each word separately.
Idiom:
behind the scenes
Meaning:
privately, out of public view
Example:
The diplomats worked behind the scenes to try and solve the crisis.
List of common idioms, their meanings and examples of their usage in sentences
The language peculiar to a people or to a district, community, or class