What is the difference between a metaphor and a simile?

What is the difference between a metaphor and a simile?

A metaphor is a figure of speech that directly compares two unrelated things, stating that one thing is another. It does not use "like" or "as" to make the comparison. On the other hand, a simile is a figure of speech that compares two unrelated things using "like" or "as" to make the comparison.