The third season of Orphan Black is coming to an end this evening, and if you haven't been watching we suggest you clone yourself and catch up double time. The hit BBC America series about clone experimentation gone awry has it all: a talented actress (Tatiana Maslany) adroitly playing multiple, multi-accented characters; backstories and references steeped in literature and myth; and, best of all, the Clone Club.

What’s the Clone Club? Check out these 15 fascinating Orphan Black terms and find out.

1. ORPHAN BLACK

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First things first: what the heck is an “orphan black”? Apparently it refers to a “child in the black,” or an orphan in hiding from the black market. Main clone (and the last one to know she is a clone) Sarah Manning and her (non-clone) foster brother Felix were both considered such children, so much so that their foster mother, Siobhan, had to smuggle them out of England.

2. LEDA

Project Leda is the initiative behind the development of a line of female clones. With the exception of Rachel Duncan, who was raised by the project’s lead scientists, the Leda clones grew up unaware of their clonage.

The name Leda comes from the Greek myth of Leda and the Swan, in which a king’s daughter is raped (or seduced, depending on the interpretation) by the god Zeus in the form of a swan. Later Leda, having also slept with her mortal husband the same night, gives birth to two eggs—one containing the mortal Castor and Clytemnestra, and the other, the divine Pollux and Helen.

3. AND 4. SARAH AND HELENA

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Clone Helena is named for the immortal Helen, and herself seems immortal, or at least very difficult to kill. Also, like Helen of Troy, Helena has a twin sister, Sarah, who, as one Redditor suggests, might be named for Sarah in the Old Testament. The Old Testament Sarah was thought to be barren but eventually bore a son. The Leda clones were developed to be infertile, but the twins aren't: Sarah has a daughter, Kira, and Helena is shown to have viable eggs.

5. COSIMA

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In addition to being a clone with enviable dreadlocks, fan favorite Cosima is a Ph.D. candidate in Experimental Evolutionary Development Biology. She’s also based on real-life Ph.D. candidate and science writer, Cosima Herter.

The real Cosima is the science consultant for the show, and in addition to checking the scripts for accuracy, she seeks the sources of inspiration for the episode titles. For season one, it was Charles Darwin's On the Origin of Species; for season two it was Francis Bacon's Plan of the Work; and this season, it's Dwight D. Eisenhower’s farewell address.

6. CASTOR

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Where there are female clones, there are male ones. While Project Leda was overseen by the scientific Dyad Institute, Project Castor is the doing of the “military faction” with the idea of creating an army of super-soldiers. The problem is, like mortal Castor, the Castor Boys are prone to death—dropping like mayflies, as Siobhan says—although it’s not (yet) clear why.

In a recent episode, the “original Castor” was found. But this original Castor turned out to be a woman with two cell lines, one male and one female, making her the original Leda as well as the original Castor and reminiscent of the original original Leda in Greek myth.

7. THE DYAD INSTITUTE

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The Dyad Institute is a biotechnology company owned by the mysterious (and probably evil) Topside corporation. The word dyad refers to duplicated chromosomes produced during mitosis, an early stage of fetal development, as well as any two individuals that are regarded as a pair. Dyad comes from a Greek word meaning “two.”

8. NEOLUTIONIST

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Dyad is headed by scientist Dr. Aldous Leekie, a famed “neolutionist,” or neo-evolutionist. Neolutionists believe that humans shouldn’t have to wait for nature to take its course in terms of evolution but should utilize technology to direct evolution themselves.

9. FREAKY LEEKIES

Fans and followers of Dr. Leekie are known as Freaky Leekies, partly because they’re freaks for the scientist but also because they dress and physically alter themselves in a way that they would consider “neolutionary” but others might deem freakish.

Aldous Leekie is most likely named for both Aldous Huxley, author of Brave New World—a dystopian novel in which “natural” reproduction has been abolished and human embryos are raised in hatcheries—and Louis Leakey, a pioneer in the study of human evolutionary development in Africa.

10. MONITORS

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Monitors are like Buffy the Vampire Slayer Watchers, only clueless. Dyad assigns each Leda clone a "monitor," usually under the guise of a significant other, who reports back to the institute on the clone's health, sleeping patterns, etc. However, the monitors don't know what their employers are up to nor do they know that their charges are clones.

11. PROLETHEAN

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The Proletheans are religious extremists divided on their views on clones. Traditional Proletheans—like those who raised Helena to be a clone-killing machine—believe clones are an abomination. A sect headed by the super-creepy Henrik Johanssen believes in the intersection of science and religion to the point of forcing women, including his own daughter, to become surrogates for “miracle” babies made with his sperm and Helena’s eggs.

The name Prolethean may have come from Lethe, the river of forgetfulness in Greek mythology. In one depiction of Leda and the Swan, Hypnos, the god of sleep, is shown drugging Leda with water from the River Lethe, the way Henrik drugged Helena before artificially impregnating her.

12. THE ISLAND OF DR. MOREAU

A copy of this novel by H.G. Wells contains all the clone secrets as written in code by Project Leda scientist—and Rachel’s adoptive dad—Ethan Duncan. In the novel, Dr. Moreau performs vivisection, or surgical experimentation, on live animals to create animal-human hybrids called “Beast Folk," only to be killed by one of his own creations in the end.

13. SESTRA

Sestra, or “sister” in various Slavic languages, is what Ukraine-bred Helena calls her fellow clones—after she decides to stop killing them, that is. “Brother-sestra” is what she calls Felix.

14. CLONE CLUB

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“You just broke the first rule of Clone Club!” says Cosima.

“What?” Sarah asks. “Never tell anyone about Clone Club?”

Those in Clone Club, both clone and non-clone, are aware of Project Leda and are against further human experimentation (unlike "proclones" like Rachel). To keep in touch, Clone Club members use burner phones they’ve dubbed "clone phones."

Clone Club—or Clone Clubbers—are also other terms for Orphan Black fans.

15. CLONE DANCE PARTY

Another good thing about Clone Club (besides being able to share clothes and DNA) is the clone dance party, which is what fans dubbed the sestras' spontaneous celebration on what they thought might be Cosima’s final night as she battled a mysterious illness.

The clone dance party itself had clones, including an extended behind-the-scenes cut and a mini-clone version created by the actress who played a younger Leda clone.