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:
since time immemorial
Meaning:
since a very long time ago
Example:
Since time immemorial people have been coming to the hot springs to bathe in the water.
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.