The suffix -nym means name. The word eponym comes from Greek eponymos, “given as a name; bestowing a name on something.”
eponym: noun. The person for whom a country or location is named. For example, Romulus is the legendary eponym of Rome. Simón Bolivar is the known eponym of Bolivia.
eponym: noun. A proper name used generically; more loosely, the generic name itself, or any noun phrase of specific meaning which includes a proper name. For example, Marxism: a theory and practice of socialism developed by or associated with Karl Marx; ohm: a unit of electrical resistance.
eponymism: noun. the practice of accounting for names of places or peoples by referring them to supposed prehistoric eponyms. In the Middle Ages, writers claimed Brutus of Troy as the eponym of Britain and the British people.
eponomy: noun. another word for eponymism.
eponymize: v. (trans.) to serve as eponym to. For example, the name Benedict Arnold has become an eponym for traitor.
eponymous: adjective. referring to an eponym. For example, Jane Eyre is the eponymous heroine of the novel by Charlotte Bronte. Another word used for eponymous is eponymic.
Many eponyms derive from Greek or Roman religious belief and practice. For example, the first six months of the year:
January: Named for Janus, the Roman god of gates and doorways, depicted with two faces looking in opposite directions
February: Named for Februa, Roman festival of purification held in that month.
March: Named for Mars, Roman god of war.
April: The name came from an Etruscan word associated with Aphrodite, Greek goddess of love and beauty.
May: Named for Maia, “the great one,” Italic goddess of spring and daughter of Faunus.
June: Named for Juno, principal Roman goddess and patroness of women and marriage. Her month is still popular with brides.
Many plant names derive from the names of the people who introduced them to their own cultures. The poinsettia is named for Joel Roberts Poinsett (1779-1851), U.S. ambassador to Mexico. German botanist Johann G. Zinn gave his name to the zinnia. Both the begonia and the bougainvillea received their names from Frenchmen: Michel Bégon (1638–1710), and Louis Antoine de Bougainville (1729–1811). A plant derivative, nicotine, takes its name from another Frenchman: Jean Nicot de Villemain (1530-1600).
A great many discoveries and practical inventions have been named for people who had little to do with them. There’s even a law for that: Stigler’s Law of Eponymy.
University of Chicago statistics professor Stephen Stigler postulated the law in an article published in 1980. The law states, “No scientific discovery is named after its original discoverer.”
Here are some examples of the truth of Stigler’s law:
America: named for Americo Vespucci, but discovered by others.
Arabic numerals: invented in India.
Fibonacci numbers: existed in Indian mathematics a thousand years earlier than Fibonacci.
Gresham’s law: described by Nicolaus Copernicus the year Gresham was born.
Halley’s comet: observed by astronomers in ancient times.
Higgs boson: named for Peter Higgs, but first theorized by Robert Brout and Francois Englert.
Stigler’s Law of Eponymy: derives from sociologist Robert K. Merton’s postulation of the Matthew effect (another eponym).
Merton studied the reward system in science and concluded that famous scientists receive disproportionate credit for their contributions. Conversely, lesser known scientists receive less credit than they deserve. Merton called this the Matthew effect. He took the name from the gospel of Matthew:
For unto every one that hath shall be given, and he shall have abundance: but from him that hath not shall be taken even that which he hath.–25:29, KJV.
In modern, noneponymous terms, “the squeaking wheel gets the oil.”