Idioms
Idioms are phrases which cannot be understood simply by looking at the meaning of the individual words in the phrase.
Idiom:
crack a book
Meaning:
to open a book to study
Example:
I did not crack a book until the last week of classes.
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.