An idiom is an expression common to a particular culture that does not mean what it literally says. You have to learn the meanings of idioms, just like you learn the meanings of words.
Similes and metaphors are both used to make comparisons.
Metaphors simply state a comparison. Similes use the words “like” or “as” to compare things. Because they both make comparisons, all similes are metaphors, but not all metaphors are similes.
Here are some examples of similes and metaphors:
Life is like a box of chocolates. (Simile)My life is an open book. (Metaphor)That baby is as cute as a button! (Simile)
Baby, you’re a firework. (Metaphor)
Adages and proverbs are types of common expressions and sayings that have meanings beyond what can be understood by their individual words.
Wise Sayings - Adages
An adage is a widely known, short but memorable saying that is considered true by many people. It expresses truth about human nature.
Wise Sayings - Proverbs
A proverb is a wise and practical saying about life in general. It is a piece of common sense expressed in a way that is easy to understand. It offers advice or instruction on how to live your life.
Common Proverbs:
Don't put all your eggs in one basket.
Meaning: to risk losing everything by putting all your efforts or all your money into one plan or one course of action
Don't throw out the baby with the bathwater.
Meaning: Don't get rid of something valuable along with something undesirable by mistake.
The early bird gets the worm.
Meaning: If you do something early or before anyone else, you will have an advantage and be successful.
A bird in the hand is worth two in the bush.
Meaning: It's better to have a lesser but certain advantage than the possibility of a greater one that may come to nothing.
A stitch in time saves nine.
Meaning: You should repair something as soon as it is damaged. If not, you will have a much bigger and more expensive repair job later. Do it now and you'll need one stitch. Do it later and you'll need 9 stitches! (Why nine and not eight or ten? Because "nine" rhymes, approximately, with "time".)