posted by tracy .
What are the sayings called ex: It is raining cats and dogs ?
It's a hyperbole.
They are called idioms. Idioms are words, phrases, or expressions that cannot be taken literally. In other words, when used in everyday language, they have a meaning other than the basic one you would find in the dictionary.
If you look up both of the answers you have been given in a dictionary, you will find that "idiom" is the better term.
I hope this helps a little more. Thanks for asking.