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:
keep up with (someone or something)
Meaning:
to go at the same speed as a person or thing, to maintain the same rate of progress as someone or something
Example:
It is difficult for the boy to keep up with the rest of the class.
List of common idioms, their meanings and examples of their usage in sentences
Idioms are phrases which cannot be understood simply by looking at the meaning of the individual words in the phrase.