metaphor: a figure of speech in which a word or phrase literally denoting one kind of object or idea is used in place of another to suggest a likeness or analogy between them
simile: a figure of speech comparing two unlike things that is often introduced by like or as
—Merriam-Webster

Both metaphors and similes explain that one thing is similar to another thing. They are tools to describe the world, often using poetic, dramatic language.

Metaphor is the overarching category of this type of description. Similes are a type of metaphor. However, we can identify similes because they use the words like or as to do their describing.

Examples of metaphors
Paul is a robot, mindlessly chugging through the workday without emotion.
After the surgery, Joe was a rag doll with stuffing poking through his seams.

We can assume that Paul and Joe are humans, but the metaphors help us understand that they are like something else. In the first sentence, Paul is compared to a robot. In the second sentence, Joe is compared to a rag doll.

However, metaphors don’t have to be so direct, as in saying, “Thing A is thing B.” Note these examples:

The mountain of debt ruined her credit.
The sea of people ran into the street.

Here, debt and people are compared to mountain and sea, respectively. Yet, they are not written directly, as in, “The debt is a mountain.”

Examples of similes
The book is like a rocket ship for my brain.
Your dancing is as weird as a polar bear juggling a penguin.

Like in the first set of examples, both sentences compare one thing to another. But, this time we know they are similes because they use like and as. The first sentence uses like to connect book to rocket ship. The second sentence uses as to connect dancing to polar bear.

Quiz
Read the sentences below and decide if each is a simile or metaphor. The answers are at the bottom.

1. Kim’s stench is like rotten eggs in a trashcan.
2. Moe is an elephant. He remembers everything.
3. The gerbil is her sun, the center of her galaxy.
4. The black hole of doubt caused Sheila to put off making her decision.
5. He’s hungry as a hippo.
6. It’s raining men. Hallelujah! It’s raining men.

Answers:

1. simile 2. metaphor 3. metaphor 4. metaphor 5. simile 6. metaphor