Question: What secret organization is Snape a part of?

Context paragraphs:
Niš rebellion (1821): The Niš rebellion broke out in Niš in 1821, suppressed by the Ottomans the same year.  It was led by a Serb revolutionary organization, the Niš Secret Organization (Hишка тајна организација), created in 1820 by Orthodox priest Melentije.  It was influenced by the Greek revolutionary organization, "Filiki Eteria" (Society of Friends).  The "muhafiz" of the Pashaluk of Niš in 1821 was Husein-paša, who was also the commander of the Niš garrison with 8,000 soldiers.

Korean Patriotic Organization: Korean Patriotic Organization (), also known as Korean Patriotic Corps or Korean Patriotic Legion, was a secret organization that aimed to assassinate prominent Japanese figures of the Empire of Japan.  It was one of the independence movements propelled by the Provisional Government of the Republic of Korea.  The Korean Patriotic Organization was founded by Kim Gu, president of the Provisional Government of the Republic of Korea.  Its executives were Kim Suk, Ahn Gong-geun, Lee Su-bong, and Lee Yu-pil.  Notable members included Yoo Sang-geun, Yoo Jin-man, Yun Bong-gil, Lee Bong-chang, Lee Duk-ju, and Choi Heung-sik.

Kolašin Affair (1909): The Kolašin Affair (Serbian: Колашинска афера ) was a rebellion in the Montenegrin military against the dictatorship of the Prince of Montenegro, Nikola I Petrović-Njegoš, that broke out in 1909.  It followed the failed Bombaš Affair (Бомбашка афера), a conspiracy organized in 1907 by a group of Montenegrin students connected to the Black Hand to break the Montenegrin government through terrorist attacks (with bombs, hence "Bombaši"), and ultimately unite Montenegro with Serbia, that was detected and led to numerous arrests in 1908.  In the same year, a secret organization of Montenegrin politicians and political emigrees in Belgrade in opposition to Nikola I was formed.  The organization's statute said that Nikola I was to be killed.  The organization planned to free the "Bombaši" and change Tomanović's reactionary regime.  The organization had important subsidiaries in Vasojevići, Kuči and Bratonožići, and allegedly had 1,000 members.  It was detected by the Montenegrin police and led to the imprisonment and death sentences of the conspirators.  The two affairs led to deteriorating bilateral relations between Montenegro and Serbia.

Sarasota Assassination Society: The Sarasota Assassination Society, also known as the Sarasota Vigilance Committee, was a late 19th-century secret organization established by Alfred Bidwell, Dr. Leonard Andrews and Jason Alford in Manatee County, Florida.  The organization, which was estimated to include twenty to twenty-two members, was purported to be a political social group or a Democratic Club.  The true aims of the group were chronicled in the February 2, 1885 "New York Times" article; “This organization is supposed to exist for the purpose of the secret murder of political opponents, and is composed of 20 members, bound together by terrible oaths to perform the bloody work of the band and to keep its secrets inviolate.”

Snape, Suffolk: Snape is a small village in the English county of Suffolk, on the River Alde close to Aldeburgh.  It has about 600 inhabitants, measured at 611 at the 2011 Census.  Snape is now best known for Snape Maltings, no longer in commercial use, but converted into a tourist centre together with a concert hall that hosts the major part of the annual Aldeburgh Festival.

Severus Snape: Severus Snape is a fictional character in J. K. Rowling's "Harry Potter" series.  An exceptionally skilful wizard, his coldly sarcastic and controlled exterior conceals deep emotions and anguish.  A Professor at Hogwarts School of Witchcraft and Wizardry, Snape is hostile to the series' protagonist, Harry, the moment he sets foot in Snape's classroom; this hostility is rooted in Harry's resemblance to Harry's father James, who bullied and harassed Snape during their time at Hogwarts.  Though philosophically attracted to the Dark Arts and Lord Voldemort's ideology of wizard supremacy, Snape's love for Muggle-born Lily Evans, Harry's mother, eventually compels him to defect from the Death Eaters.  Snape becomes a double-agent on behalf of Albus Dumbledore and the Order of the Phoenix, and protects Harry throughout the series.

Macedonian Society: The Macedonian Society or Secret Macedonian Society (Macedonian: Тајниот македонски комитет ) was secret organization established in 1886 by Macedonian Slavs in Sofia, Bulgaria, to promote a kind of Macedonian pro-Serbian identity, distinguished especially from the ethnic identity of the Bulgarians.  Its leaders were Naum Evrov, Kosta Grupčev, Vasilij Karajovev and Temko Popov.

The Street (novel): The Street is a novel published in 1946 by African-American writer Ann Petry.  Set in World War II era Harlem, it centers on the life of Lutie Johnson.  Petry's novel is a commentary on the social injustices that confronted her character, Lutie Johnson, as a single black mother in this time period.  Lutie is confronted by racism, sexism, and classism on a daily basis in her pursuit of the American dream for herself and her son, Bub.  Lutie fully subscribes to the belief that if she follows the adages of Benjamin Franklin by working hard and saving wisely, she will be able to achieve the dream of being financially independent and move from the tenement in which she lives on 116th Street.  Franklin is embodied in the text through the character Junto, named after Franklin's secret organization of the same name.  It is Junto, through his secret manipulations to possess Lutie sexually, who ultimately leads Lutie to murder Junto's henchman, Boots.  Junto represents Petry's deep disillusionment with the cultural myth of the American dream.

Order of the Phoenix (fictional organisation): The Order of the Phoenix is a secret organisation in the "Harry Potter" series of fiction books written by J. K. Rowling.  Founded by Albus Dumbledore to fight Lord Voldemort and his followers, the Death Eaters, the Order lends its name to the fifth book of the series, "Harry Potter and the Order of the Phoenix".

Ellinoglosso Xenodocheio: The Ellinoglosso Xenodocheio (Greek: Ελληνόγλωσσο Ξενοδοχείο , "Hellenophone Hotel", meaning "Greek-speaking Hotel"), was a secret organization established in Paris in 1814, whose purpose was to educate the Greeks and prepare the struggle against Ottoman rule over Greece.  Two of its founders were the Macedonian Grigorios Zalykis and the Epirote Athanasios Tsakalov.  The organization was a precursor of another organization, Filiki Eteria, of which Athanasios Tsakalov was a founding member and which succeeded in mobilizing Greeks against the Ottoman Empire culminating in the Greek War of Independence.

Supporting paragraphs: Severus Snape Order of the Phoenix (fictional organisation)
Answer: Order of the Phoenix