An ELT Glossary : Figure of Speech / Metaphor / Simile

A figure of speech is a word or phrase that is used not literally, but whose literal sense is understandable and creates an image in the listener or reader's mind which will convey the meaning that the speaker/writer wishes to convey. Two common figures of speech are metaphor and simile.

A metaphor is a figure of speech in which a word is used not literally, but to imply a comparison. For example :

He wasn't just angry - he was at boiling point.
The rain was bucketing down .
She's a real dragon.
I was shattered at the news

Metaphor is slightly different from  simile, in that in metaphors the comparison is implicit, whereas in a simile it is explicit, and signalled by words such as than, like or as :

She ran faster than lightning.
She ran like the wind.
His hands were as cold as ice.

See also : My teacher is an old cow : Teaching figurative language, should we or shouldn't we?