An eponym is a word or name derived from a person. When a disease, place, invention, or idea gets its name from someone, that name is an eponym. You encounter eponyms constantly, from the countries on a map to the units on your electricity bill, even if you’ve never heard the term itself.
The word comes from ancient Greek: “epi” (upon) and “onyma” (name), literally meaning “named upon” someone. In its original Greek context, it described the heroes and founders whose names were given to tribes and cities. Today it applies far more broadly.
How Eponyms Work
An eponym can go in two directions. A person can give their name to something (Alessandro Volta giving his name to the “volt”), or a person’s name can become so associated with a concept that it turns into a general word. Either way, a proper noun gradually becomes part of everyday vocabulary. Sometimes the connection to the original person fades entirely. Most people who say “heroin” or “escalator” have no idea those were once brand names tied to specific companies and individuals.
The Oxford English Dictionary captures this dual nature in its definition: an eponym is both the person who gives their name to something, and the name itself once it has taken on independent meaning.
Eponyms in Medicine
Medicine is packed with eponyms. Many of the most recognizable disease names honor the physicians or researchers who first described them:
- Parkinson’s disease is named after James Parkinson, who described it as “paralysis agitans.”
- Alzheimer’s disease comes from the German psychiatrist Alois Alzheimer.
- Hodgkin’s disease (a type of lymphoma) is named after Thomas Hodgkin.
- Crohn’s disease carries the name of Burrill Crohn, who identified the inflammatory bowel condition.
- Graves’ disease (a thyroid disorder) is named after Robert James Graves.
- Hashimoto’s disease (another thyroid condition) comes from the Japanese physician Hakaru Hashimoto.
- Cushing’s disease is named after the neurosurgeon Harvey Cushing.
A 2017 study tracking the fate of over 8,600 medical eponyms found that more publications used an eponym in their title in 2014 than at any previous point in history. At the same time, the proportion of medical papers using eponyms in their titles has dropped from a peak of about 3% in 1991 to around 2%. New eponyms are also being coined less often: the rate of “extinction” (eponyms falling out of use) overtook the rate of new coinage back in the 1980s. So medical eponyms are far from dead, but the field is gradually shifting toward descriptive names.
One reason for the shift is practical. A name like “Graves’ disease” tells you nothing about what the condition actually involves, while “autoimmune hyperthyroidism” gives you a clue. As a commentary in Nature pointed out about physics, a term like “quantum wave equation” would be immediately informative in a way that “Schrödinger’s equation” is not, since the latter requires you to already know the reference.
Eponyms in Science and Measurement
Physics and engineering run on eponyms. Many of the standard units of measurement are named after scientists: volts (Alessandro Volta), ohms (Georg Ohm), hertz (Heinrich Hertz), tesla (Nikola Tesla), and ångströms (Anders Ångström). Students learn Newton’s laws, Maxwell’s equations, the Schrödinger equation, and Heisenberg’s uncertainty principle as foundational concepts, with each name serving as a shorthand for a body of work.
These names sometimes oversimplify history. Take Maxwell’s equations: their commonly used form of four compact vector equations appears nowhere in James Clerk Maxwell’s original 1861 paper, which contained 20 differential equations with 20 variables. The streamlined version used today was largely the work of Oliver Heaviside. And each of the four equations within the set has its own eponym: Gauss’s law, Gauss’s law for magnetism, Faraday’s induction law, and Ampère’s circuit law. Attribution, in other words, can be layered and sometimes misleading.
Eponyms in Geography
At least 18 countries have names clearly derived from real historical figures, with another 10 or so having uncertain connections. Bolivia is named after Simón Bolívar, the South American independence leader, who also lends his name to Venezuela’s official title (the Bolivarian Republic of Venezuela). The Americas themselves are named after the Italian explorer Amerigo Vespucci. Some geographic eponyms trace back to mythological or semi-legendary figures: Greece’s official name, the Hellenic Republic, derives from Hellene, a figure from Greek mythology, and Romania may trace its name back to the legendary Romulus.
Cities follow the same pattern. Washington, D.C. honors George Washington. Alexandria was named by Alexander the Great. Constantinople carried the name of the Roman emperor Constantine for over 1,500 years.
Brand Names That Became Generic Words
A special category of eponyms involves brand names that escape their trademarks and become everyday words. These are sometimes called proprietary eponyms or genericized trademarks. “Escalator” was originally trademarked by the Otis Elevator Company until 1950. “Dry ice” was a registered trademark of the Dry Ice Corporation of America starting in 1925. “Heroin” was trademarked by the pharmaceutical company Bayer in 1898, then lost as a trademark in several countries through the Treaty of Versailles in 1919. “Trampoline” belonged to the Griswold-Nissen Trampoline & Tumbling Company. Linoleum, coined by Frederick Walton in 1864, was ruled generic after a trademark lawsuit in 1878, making it likely the first product name to become a common word.
In the UK, “Sellotape” is used generically for any transparent adhesive tape. “Thermos” lost its trademark status in the United States in 1963, though it remains protected in other countries. These transitions happen when a brand so thoroughly dominates a product category that consumers stop distinguishing between the brand and the thing itself.
The Possessive Problem
If you’ve ever seen both “Parkinson’s disease” and “Parkinson disease,” you’ve noticed the possessive debate. Major organizations including the World Health Organization and the American Medical Association have long recommended dropping the possessive form. Their reasoning: the person the disease is named after didn’t own the disease or necessarily even have it. Despite these guidelines, the possessive form remains deeply embedded in everyday language. Most people say “Alzheimer’s,” not “Alzheimer disease,” and many medical journals still accept either form.
The Ethics of Naming
Some medical eponyms have come under scrutiny because of the histories of their namesakes. Hans Reiter, whose name was attached to a form of reactive arthritis, was a Nazi war criminal. Friedrich Wegener, namesake of a serious blood vessel disease, was a member of the Nazi party. In both cases, the medical community has increasingly moved toward descriptive alternatives. Reiter’s syndrome is now more commonly called “reactive arthritis,” and Wegener’s granulomatosis has been renamed “granulomatosis with polyangiitis.”
These changes reflect a broader conversation in science about whether honoring someone with an eponym is appropriate when their personal history involves serious ethical violations. The shift is slow and uneven, but the direction is clear: when a descriptive name exists and the namesake’s legacy is problematic, institutions are choosing to move on.