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:
up to the mark
Meaning:
meeting normal standards, equal to the usual level or quality
Example:
The work was not up to the mark and the company would not pay for it.
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