What is metaphor?

"You're a peach!" We've all heard the expression, and it's a good example of what we call metaphor. A metaphor is a figure of speech in which a word or phrase denoting one kind of object or action is used in place of another to suggest a likeness or analogy between them: the person being addressed in "you're a peach" is being equated with a peach, with the suggestion being that the person is pleasing or delightful in the way that a peach is pleasing and delightful. A metaphor is an implied comparison, as in "the silk of the singer's voice," in contrast to the explicit comparison of the simile, which uses like or as, as in "a voice smooth like silk."

When we use metaphor, we make a leap beyond rational, ho-hum comparison to an identification or fusion of two objects, resulting in a new entity that has characteristics of both: the voice isn't like silk; it is silk. Many critics regard the making of metaphors as a system of thought antedating or bypassing logic. Metaphor is the fundamental language of poetry, although it is common on all levels and in all kinds of language.

Lots of common words we use every day were originally vivid images, although they exist now as dead metaphors whose original aptness has been lost. The word daisy, for example, comes from an Old English word meaning "day's eye." The ray-like appearance of the daisy, which opens and closes with the sun, is reminiscent of an eye that opens in the morning and closes at night. The expression time flies is also metaphorical, with time being identified with a bird.

In poetry a metaphor may perform varied functions, from noting simple similarity between things to evoking a broad set of associations; it may exist as a minor element, or it may be the central concept and controlling image of the poem. The metaphor of an iron horse for a train, for example, is the elaborate central concept of one of Emily Dickinson's poems—though neither iron horse nor train appears in the poem, the first and final stanzas of which are:

I like to see it lap the Miles—

And lick the Valleys up—

And stop to feed itself at Tanks—

And then—prodigious step

…

And neigh like Boanerges—

Then—prompter than a Star

Stop—docile and omnipotent

At it's own stable door—

A mixed metaphor is the linking of two or more elements that don't go together logically. It happens when the writer or speaker isn't being sensitive to the literal meaning of the words or to the falseness of the comparison being used. A mixed metaphor is often two metaphors sloppily mashed together as in, "the ball is in the court of public opinion," which joins "the ball is in your court" to "the court of public opinion."

A mixed metaphor may also be used with great effectiveness, however, as in Hamlet's speech:

Whether 'tis nobler in the mind to suffer

The slings and arrows of outrageous fortune

Or to take arms against a sea of troubles

For strictly correct completion of the metaphor, sea should be replaced by a word like host. By using "sea of troubles," however, Shakespeare evokes the overwhelming nature of Hamlet's troubles.

Simile vs. Metaphor

Many people have trouble distinguishing between simile and metaphor. A glance at their Latin and Greek roots offers a simple way of telling these two closely-related figures of speech apart. Simile comes from the Latin word similis (meaning “similar, like”), which seems fitting, since the comparison indicated by a simile will typically contain the words as or like. Metaphor, on the other hand, comes from the Greek word metapherein (“to transfer”), which is also fitting, since a metaphor is used in place of something. “My love is like a red, red rose” is a simile, and “love is a rose” is a metaphor.