Simile -- A common device in poetry is the use of comparisons, often comparing something unusual or uncommon with something that is more familiar to the reader or audience. One kind of comparison is the simile, which uses the words like or as and compares two things that are dissimilar in order to bring about a fresh view and new meaning.
An example of a simile that does this is found in Margaret Atwood's "You fit into me," in which she describes the fit of two lovers to each other as "like a hook into an eye." The reader imagines a hook and eye on the band of a skirt or the back of a bra, but then Atwood changes the significance of the simile by becoming more specific. She adds the explanation "A fish hook ... An open eye." The extended simile creates a very painful image of being a woman stuck with someone who isn't good for her, who perhaps abuses her, or even rapes her. Not everyone has had such a relationship or been the victim of an unpleasant or painful sexual experience, but most people know that a fishhook has a barb on it that tears the flesh when it is pulled out. And everyone knows that the eye is particularly sensitive, valuable to one's survival, and important to one's appearance and identity. So a fishhook pulled from a human eye would leave a lasting injury with blurred or damaged vision, constant watering, pain, disfigurement, etc. Damage to the substance of the eye is a violent image. Whatever the experience of the relationship was, it was traumatic, caused enormous pain, and extended grief and tears.
Metaphor -- Two kinds of comparisons are used in poetry. One is the simile, just discussed, the other is metaphor, which is like a condensed form of simile or comparison, in which the words like and as are not used, but the poet goes straight to the meaning. An example of a metaphor is found in Emily Dickinson's poem "Wild Nights -- Wild Nights!" In the poem she wistfully imagines what it would be like to be with the man she loves -- wildly passionate and luxurious. In the second stanza she juxtaposes this image against contrasting images of safety. She places herself and her lover in a safe port while a storm at Sea is taking place outside where it cannot harm them ("Futile -- the Winds -- To a Heart in port). She is not "at Sea" anymore ("Done with the Compass -- Done with the Chart!") but safe in the arms of the beloved. "At Sea" may be a metaphor for indecision or for emotional tumult, or both.
In the last stanza the poet uses the Sea again as a metaphor but this time a more peaceful one (like the afterglow of lovemaking) in which rowing is taking place in the placid waters of Paradise: "Rowing in Eden -- Ah, the Sea!" The Sea is a very apt metaphor for passion because waves rise and fall as passion does. When the Sea is agitated, it is very exciting and tumultuous, and these words could be applied equally well to human beings when they are aroused sexually. Moreover, the ocean is powerful and uncontrollable, which implies that the poet's passion would carry her away. A metaphor, like a condensed kernel or seed, grows into more meaning; in fact, its significance develops and blooms in a way that pages of prose could not. Metaphor says things prose cannot say and remain open to the development of interpretation.
Personification - Another poetic device is personification in which something that is not human, an animal, thing, or phenomenon is spoken to or about as though it were a person. In his poem "Death Be Not Proud," John Donne speaks of death as though death were a prideful, mortal man whom he (the poet) intends to take down a notch from his loftiness. Death is not a human being, of course, but an experience which some people (poet included) see as transitional from one stage of existence to another ("One short sleep past, we wake eternally,"). But because so many people are afraid of death, the poet personifies death in order to show that the concept of death has been overblown and invested with power that it does not really have -- like a man who has grown "too big for his britches," he speaks directly to death: "Death, be not proud, though some have called thee mighty and dreadful, for thou art not so;" and then goes on to say that the people Death thinks he has killed, are not really dead but only sleep awhile until they awaken to eternal life.
Speaking directly to death as though the phenomenon were a person, the poet shows that death is an illusion. Everyone experiences it, but nobody dies from it. Once human beings understand that, death loses its power over them because an illusion has no power once the truth is known: "And death shall be no more; death, thou shalt die" means that the belief that death is the end of a person's identity will disappear.
Metonymy - When a poet uses a term closely associated with what he is really talking about, the device is known as metonymy. For example, in "A man said to the universe," Stephen Crane substitutes "the universe" to mean God (in the same way we speak of "Washington" to mean the government of the United States of America). We know he really means God because in the poem the universe speaks back as though it were a sentient being with a sense of identity who speaks of itself as "me." The universe, that is, the sun, moon, planets, stars, etc. could not feel a sense of obligation or speak about it. And God as the All in All is more than the universe because the universe includes only what is seen, while God includes all that is not seen.
Perhaps, the poet uses metonymy because the universe immediately evokes images of vastness and unfathomable distances, while God may or may not evoke such images. Some people still conceive of God as an old man with a long beard sitting on a throne somewhere far-off keeping track of the behavior of human beings on earth. This is a very limited concept of God, which the poet perhaps hoped to avoid. The universe presents a contrasting backdrop for the insignificance of human beings when compared to the vastness of space, and this seems to be part of the message of the poem. Plus, the universe is impersonal in contrast to the idea that God knows each one of us intimately as an expression of His being. That is not the idea the poet wants to impart. The universe can be more easily pictured as uninvolved in man's existence and, and according to the poet, disinterested.
Hyperbole - Another word for exaggeration is hyperbole. Poets often use it to achieve humor because hyperbole becomes more and more ridiculous the farther it is taken. It is not a rule, however, that hyperbole is only to achieve humor. In Richard Cory, for example, Edwin Arlington Robinson uses hyperbole to achieve an image of perfection in a human being, which he then completely destroys in the last line of the poem. In this case, hyperbole functions to increase the poem's shock value at the end. The poet wants the reader to experience the same shock he felt when he learned that Richard Cory had killed himself.
The narrator starts by describing Richard Cory's physical appearance, as though he were society's idea of the ideal man. He is well-dressed "from sole to crown," always clean, well cared-for, and slender. Slender implies that his clothes fit him perfectly and hang well. In the second verse we learn about Richard Cory's perfect manners. He speaks quietly and is always personable and makes an impression on people, causing "fluttered pulses when he said, 'Good Morning ....'" Not only are his manners lovely but he's sexually attractive as well, and "he glittered when he walked." To glitter when he walked implies he carried an aura of wealth and privilege. Perhaps he wore jewels as well. In the next stanza we learn that Richard Cory was rich -- "richer than a king" (a specific incidence of hyperbole, since nobody is richer than the King is), gracious, "fine," and enviable. Finally, the poet contrasts the position, wealth, and beauty of Richard Cory to the rest of poor humanity: "We worked and waited for the light, and went without the meat and cursed the bread." This is certainly accurate for how some poor people live, but not all poor people are so miserable. He exaggerates to make the contrast greater. Then the poet hits us with the shocker: "And Richard Cory, one calm summer night, went home and put a bullet through his head." The hyperbole builds gradually in the…