"The entire point of using a symbol is that it conveys meaning and saves space -- you see one picture of a stick figure in a dress and you no longer need the phrase "This is the place where female humans can discharge waste." But what is fascinating is that sometimes the meaning of a symbol will get lost to history, but we'll just keep right on using it anyway.
But would we do that if we knew ...
#6. The Jesus Fish Is a Vagina
Apart from the cross, the most ubiquitous symbol of Christianity is the ichthys, known to us as the Jesus Fish, and today it appears predominantly in its natural habitat -- car bumpers. The ichthys actually dates right back to ancient times, when Christianity was still an obscure sect, and considering that fish and fishing were frequently used as symbols in the Bible, you could argue that it's a more appropriate symbol for the teachings of Christ than the device used to torture and kill him.

"Seriously, guys? Do you wear tiny rifle necklaces to remember Martin Luther King Jr.?"
The Origin:
It's a vagina.
One of the names given to the pre-Jesus Jesus Fish is the vesica pisces (vessel of the fish), and it was used as a symbol of every female fertility god ever, from Atargatis (the Syrian fertility goddess), Aphrodite/Venus (the goddess of love and sex) to the pagan Great Mother goddess, where it symbolized her life-giving vulva. Basically, whenever you encountered an image of fish in the pre-Christian world, it was probably an opposite-of-subtle metaphor for lady parts.
Jez
According to some researchers, Christians adopted the vagina-fish symbol simply because of how common it was, but later looked for all sorts of non-vaginal justifications for it. Even actual Christian scholars admit that their second most popular symbol has a colorful history, just not one you want to bring up during a family dinner party.

Or sex.
#5. The Heart Symbol Is About Birth Control (and Balls)

It's one of the most ubiquitous symbols on the planet, appearing everywhere from cards to candy to jewelery to bikers' tattoos. The common heart shape is such a part of everyday life, in fact, that it's easy to overlook the fact that it actually looks nothing whatsoever like a heart. What's with that?

"My love for you is like a kidney, in that it filters out the bad stuff, like that time you had sex with Mandy."
Well, there's some pretty convincing evidence that it was never supposed to be a heart in the first place, but rather ...
The Origin:
A contraceptive from the Roman era.
If you trace the heart symbol back as far as you can, you wind up finding it on old Roman coins, like this one:
But that's not supposed to be someone's cardiac muscle. That's the seedpod of the silphium plant, a herb so prized for its birth control capabilities that the Romans literally fucked it to extinction.
But while it existed, depictions of its seeds were widespread across the Roman Empire, to the point where it appeared on their money. To get a proper grasp of how much the Romans liked to hide the sausage, imagine if the Founding Fathers had printed a picture of a condom on the dollar bill.

The conspiracy theories would be a lot more entertaining.
Historians aren't absolutely certain that this was the origin of the symbol we use today, rather than some crazy coincidence, but it beats our best alternative theory, which is "Damned if we know." If true, then the universal symbol for love began as the universal symbol for hard dicking, which kind of makes your Mother's Day card a little awkward.
We can still trump that, though. See, the Romans did liken the shape of the silphium plant to a bodily organ, but it wasn't the heart. To see the original design, you have to flip the image upside-down.

And imagine it dangling above your face after getting ganked in, oh, any shooter ever.
That's right. The box of candies you bought your girlfriend for Valentine's Day is actually a bunch of multicolored, dangling nutsacks.
#4. The Peace Sign Is a Depressed Stick Man

The peace sign remains one of the most powerful and inspiring symbols on the planet, despite its long association with hippies. Maybe it's the simple geometric shapes that speak to some primal part of our brains, but looking at it, you do feel this sort of grandiosity, hope and conviction from it.
Unfortunately, all of that's basically the polar opposite of what the symbol's creator had in mind.
The Origin:
Originally, it was an image of a dude slumped over in despair.
Gerald Holtom, a British graphic designer, came up with the peace sign design in 1958 to be used at a protest against nuclear weapons. It's actually a kind of double entendre: People have adopted one interpretation of the symbol, two superimposed semaphore letters -- N and D -- which were meant to stand for "nuclear disarmament."
But what we've forgotten was the primary image that Holtom was trying to portray: In his own words, his logo was meant to be a "human being in despair." The inspirational peace sign is in actuality a representation of a man who has lost hope in a world gone mad, stretching his arms out and downward in desperation and defeat.

Oh yeah, we see it.
Holtom immediately regretted his depressing-as-hell image after it went mainstream and tried to change it by flipping it upside-down so that the arms were stretched up into the air. He could even have kept his semaphore imagery, because the V-shape in semaphore is a U, for "unilateral."
But the alternative version failed to catch on. Instead, a depressed and defeated stick man became the inspirational symbol for every progressive movement of the late 20th century, from Vietnam to civil rights. We can suppose it wouldn't have caught on so well if he had gone with his alternative design of a stick man quietly slashing his own wrists.

"Next on Scooby-Doo -- the mystery of why no one understands our pain."
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