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:
nod off
Meaning:
to fall asleep (usually while sitting or driving etc.)
Example:
I nodded off last night while I was watching television.
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 other than its literal meaning of the words in it.