Title text: I just call all of them 'synecdoche'.
This comic revolves around the similarities (and differences) between the concepts of "Analogy", "Simile" and "Metaphor" (and "Synecdoche"(and "sandwich")).
The dictionary defines a "metaphor" as a figure of speech that uses one thing to mean another and makes a comparison between the two. For example, Shakespeare's line, "All the world's a stage," is a metaphor comparing the whole world to a theater stage. Metaphors can be very simple, and they can function as most any part of speech. "The spy shadowed the woman" is a verb metaphor. The spy is not literally her shadow, but he follows her so closely and quietly that he resembles one.
A "simile", also called an open comparison, is a form of metaphor that compares two different things to create a new meaning. But a simile always uses "like" or "as" within the phrase and the comparison is more explicit than a metaphor. For example, Shakespeare's line could be rewritten as a simile to read: "The world is like a stage." Another simile would be: "The spy was close as a shadow." Both metaphor and simile can be used to enhance writing.
An "analogy" is a bit more complicated. At the most basic level, an analogy shows similarity between things that might seem different — much like an extended metaphor or simile. But analogy isn't just a form of speech. It can be a logical argument: if two things are alike in some ways, they are alike in some other ways as well. Analogy is often used to help provide insight by comparing an unknown subject to one that is more familiar. It can also show a relationship between pairs of things. This form of analogy is often used on standardized tests in the form "A is to B as C is to D".
Einstein famously used analogies to explain how radio works: "You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat." Unfortunately, nobody was any the wiser after hearing this.
"Synecdoche" is the naming the whole of something by referring to a part, or vice versa. E.g. using "the Internet" when meaning "the World Wide Web", which is only a part of it; or using "Band-Aid" when referring to any adhesive bandage. Randall is saying that he doesn't really understand the difference between them, but instead of using one of the names as a placeholder for them all (that is, as a synecdoche), he actually uses the word 'synecdoche'. What a mind he has.
- [Two men sit in front of the TV, one on the couch, the other on the floor. Megan stands by the TV set.]
- Megan: While I'm up, does anyone want a sandwich?
- Cueball: Is "sandwich" a metaphor?
- Megan: No, I'm bad at metaphors. But I could try a simile.
- Cueball: I guess that's like a metaphor. Sure.
- [As Megan starts to walk away, the men continue to speak.]
- Friend: Well, "a simile is like a metaphor" is a simile.
- Cueball: Is that simile itself a metaphor for something?
- Friend: Maybe it's a metaphor for analogy.
- [The two men are still sitting in the same place while Megan is out of the panel.]
- Cueball: Similes are metaphors in that they're both analogies.
- Megan: Analogies are like sandwiches in that I'm making one now.