Many people confuse these two words.

Problem:
These two nouns are not synonyms.

Explanation:
A simile is a comparison of two unlike things using “like” or “as”.

The origin of the word “simile” is a Latin noun that means likeness.

A metaphor is a comparison that does not use “like” or “as”.

The origin of the word “metaphor” is a Greek verb that means to transfer.

So another way to think of a metaphor is that it acts like a symbol for something else.

Solution:
A comparison is a simile when it involve “like” or “as”; a metaphor never involves either of these prepositions.