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:
go to the expense (of doing something)
Meaning:
to pay the cost of doing something
Example:
We had to go to the expense of buying a new tent for camping.
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