Editing Tip: Eponyms

  • An eponym is a type of noun or phrase that is based on a person's name (e.g., einsteinium)

Updated on July 23, 2013

Scientific writing often involves describing new results based on observations and techniques originally described by others. In many of these cases, citing previous work provides the link to the past, but some researchers have become immortalized in common terms and phrases. This tip takes a look at these special terms, called eponyms.

Eponyms in scientific writing often involve a name used in a descriptive manner (as an adjective), followed by the type of entity they described (Achilles tendon, Boltzmann constant, Van der Waals force). Other terms are directly derived from a name but stand alone, e.g., torr (the unit of pressure) or elements such as nobelium. Here are a few things to keep in mind when using eponyms in your writing:

Use of the possessive form

Many older eponyms include a possessive form (that is, the 's in phrases such as Tukey's test). However, recent style guides from organizations such as the World Health Organization and the American Medical Association have advocated against the possessive form in favor of a simple adjectival construct (e.g., Parkinson disease instead of Parkinson's disease). While conventions vary by journal, and the movement toward nonpossessive terms is slow in some areas, it is generally preferable to avoid the apostrophe:

  • cesarean section
  • Down syndrome
  • Hodgkin disease
  • Schwann cell

Note that some possessive forms still exist and are used almost exclusively (especially Student's t-test). In such cases, be sure that the possessive form is not preceded by an article (that is, not the Student's t-test).

Use of articles with eponyms

We've just mentioned that no article belongs with possessive forms, but can articles ever be used with eponyms? Sometimes, the nonpossessive form is most frequently used with the article the in front, as in the examples that follow. Unfortunately, there is no good rule for when to use an article, so pay attention to the papers in your field or use Google Scholar to see which form is more common.

  • the Carvallo sign
  • the Fisher exact test
  • the Starling law
  • the Pascal principle

Capitalization of eponyms

Because they are based on a proper noun (the person for whom the term is named), many eponyms include a capital letter, especially when the name is serving as an adjective in an unaltered form. However, when the derivative words are created from a name, they are generally spelled with a lowercase letter:

  • gram-negative bacteria (but: Gram stain)
  • hunterian chancre (but: Hunter sore)
  • müllerian duct (but: duct of Müller)
  • parkinsonian tremor (but: Parkinson disease)

We hope that today's tip gives you a little background on the eponyms in your writing and how to use them. If you have questions about a particular term, write us an email at [email protected]. Thanks for reading, and best of luck with your research and writing!

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