Let’s begin with this from http://copyblogger.com
Common sources of confusion for the metaphorically inclined include the simile and the analogy. While all three are closely related, it’s smart to understand the differences. The distinctions among metaphors, similes, and analogies will also help to underscore why you may want to use one and not the other in certain situations.
Let’s take a look at definitions:
Metaphor: A metaphor is a figure of speech that uses one thing to mean another and makes a comparison between the two. The key words here are “one thing to mean another.” So, when someone says “He’s become a shell of a man,” we know not to take this literally, even though it’s stated directly as if this person had actually lost his internal substance.
Simile: A simile compares two different things in order to create a new meaning. In this case, we are made explicitly aware that a comparison is being made due to the use of “like” or “as” (He’s like a shell of a man).
For fun, the next time someone corrects you and says “That’s a simile, not a metaphor,” you can respond by letting them know that a simile is a type of metaphor, just like sarcasm is a type of irony. Resist the urge to be sarcastic in your delivery.
Analogy: An analogy is comparable to metaphor and simile in that it shows how two different things are similar, but it’s a bit more complex. Rather than a figure of speech, an analogy is more of a logical argument. (More of? An argument is either logical, or it isn’t LOL!)
The presenter of an analogy will often demonstrate how two things are alike by pointing out shared characteristics, with the goal of showing that if two things are similar in some ways, they are similar in other ways as well.
IS THAT CLEAR? Of course not:
(Pretend you’re at the eye doctor looking through the instrument that tries out different lens configurations)
How about this?
Is this better?
Maybe bifocals would be appropriate at your age…no? Let’s try this…