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:
keep (someone) in line
Meaning:
to make someone behave properly
Example:
The teacher is very strict and she knows how to keep her students in line.
List of common idioms, their meanings and examples of their usage in sentences
An idiom is a group of words, or in other words, a phrase that has a meaning different from the literal meaning of the words in it.