Idioms
An idiom is a type of phrase or expression that has a meaning that can't be deciphered by defining the individual words.
Idiom:
set one's mind at rest
Meaning:
to free oneself from worry, to stop worrying
Example:
I told my father the reason that we cannot come in order to set his mind at rest.
List of common idioms, their meanings and examples of their usage in sentences
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.