Figurative language refers to words or phrases that do not have the same meaning as their literal meaning. Authors use a variety of types of figurative language in order to convey their message. These devices are most common in poetry, but can be used in other forms of writing, as well. Sometimes figurative language adds a deeper meaning or humor to a text.
Writers often compare one thing to something else, to help the reader see the object or person in a new light. Similes are figurative devices that compare things using the words "like" or "as." For example, "she shines like the sun," is a simile. A metaphor also compares two things, but doesn't use "like" or "as." "That pig cheated on her" is an example of a metaphor.
Personification gives non-humans human-like qualities. For example, "the flag danced in the wind" and "traffic was crawling" are examples of personification. Personification also involves using pronouns to refer to objects. For example, calling a boat "she" is personification.
Hyperbole involves exaggerating to make a point. One example of hyperbole is saying, "I told you a million times not to do that."
Onomatopeia refers to words that sound like the thing they are describing. For example, the word "zip" sounds like the sound a zipper makes, and the word "drip" sounds like water dripping.
An idiom is a common phrase, and is often a cliche. Two idioms in American English are "made of money" and "off the record."
Synecdoches use a part of something to refer to the whole. For example, when you ask someone to "lend you a hand," you are actually referring to the entire person---you don't really just want his hand.
A pun is a play on words. A writer can use similar-sounding words to convey two meanings. Puns usually aim to be humorous.