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:
black out
Meaning:
to faint or pass out
Example:
The young woman blacked out while she was standing in front of the computer.
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