Nonpossessive Form - Eponyms

AMA Manual of Style - Stacy L. Christiansen, Cheryl Iverson 2020

Nonpossessive Form

There is some continuing debate about the use of the possessive form for eponyms, but a transition toward the nonpossessive form has taken place. A major step toward preference for the nonpossessive form occurred when the National Down Syndrome Society advocated the use of Down syndrome, rather than Down’s syndrome, explaining that the syndrome does not actually belong to anyone.1 Previous editions of this manual,2 the Council of Science Editors style manual,3 and the 28th edition of Stedman’s Medical Dictionary4 recommend and use the nonpossessive form for eponymous terms. However, the 32nd edition of Dorland’s Illustrated Medical Dictionary takes an intermediate position, stating, “The tendency in recent years has been to drop the ’s from medical eponyms and to use the nonpossessive form of the personal name. . . .This decision should by no means, however, be taken as a proscription of the possessive eponym, and whether or not to use the possessive is very much a matter of individual preferences.”5 The use of the possessive form for eponyms is becoming progressively less common, and the entries for eponymic terms in dictionaries reflect this ongoing shift in usage.

One reason for preferring the nonpossessive form is that although eponyms are possessive nouns using proper names, they are structurally adjectival and should not convey a true possessive sense. For example, the name Addison, as used in describing “Addison’s disease,” is used as a noun modifier, with the sense of the modifier being clearly nonpossessive. Some possessive eponyms have evolved into the form of derived adjectives, as exemplified in the term addisonian crisis. Even when eponyms are used in an attributive sense, they have commonly lost possessive endings over time (eg, Nobel Prize). Thus, the transition of eponyms to the nonpossessive form is consistent with a linguistic perspective and with trends in English usage.

Use of the nonpossessive form of eponyms has become standard in medical genetics, and such usage, recommended by McKusick in Mendelian Inheritance in Man: A Catalog of Human Genes and Genetic Disorders,6 is appropriate in other areas of medicine. McKusick’s reasons for avoiding the possessive form of eponyms included the comment that “the eponym is merely a ’handle’; often the person whose name is used was not the first to describe the condition . . . or did not describe the full syndrome as it has subsequently become known.” Hence, even the initial description may not belong to the named individual, providing an additional reason to avoid the possessive form.

Use of the nonpossessive form can avoid awkwardness that otherwise would occur in instances such as the following:

When the word following begins with a sibilant c, s, or z (syndrome, sign, zone)

When an eponym ends in ce, s, or z

When a hyphenated name is involved

 Brown-Séquard syndrome

When 2 or more names are involved:

 Charcot-Marie-Tooth disease

 Dejerine-Sottas dystrophy

 Tay-Sachs disease

When an article (a, an, the) precedes the term:

 an Opie paradox

 a Schatzki ring

Alternative stylings for eponymous terms may include the preposition of:

angle of Virchow

circle of Willis

The possessive form may be used when it is part of an established nonmedical eponymous name:

Russell’s viper

St John’s wort (Hypericum perforatum)

The possessive form is retained if it is part of the name of an organization or title or was used in the original quotation or citation:

Alzheimer’s Association

Dorland’s Illustrated Medical Dictionary

The possessive form is also retained for noneponymous terms that describe disorders characteristic of certain occupations or activities:

woolsorter’s disease

gamekeeper’s thumb

With the exceptions noted herein, the nonpossessive form should be used for eponymous terms.

Principal Author: Brenda Gregoline, ELS


I thank Karen Boyd and Diane L. Cannon, formerly of JAMA Network; Barbara Gastel, MD, MPH, Texas A&M University, College Station; and Peter J. Olson, ELS, Sheridan Journal Services, Waterbury, Vermont, for their review of this chapter.


1.The National Down Syndrome Society. Preferred language guide. Accessed December 4, 2018.

2.Iverson C, Christiansen S, Flanagin A, et al. AMA Manual of Style: A Guide for Authors and Editors. 10th ed. Oxford University Press; 2007.

3.Style Manual Committee, Council of Science Editors. Scientific Style and Format: The CSE Manual for Authors, Editors, and Publishers. 8th ed. University of Chicago Press/Council of Science Editors; 2014.

4.Stedman’s Medical Dictionary. 28th ed. Lippincott Williams & Wilkins; 2005.

5.Dorland’s Illustrated Medical Dictionary. 32nd ed. Saunders; 2012:xx-xxi.

6.McKusick VA. Mendelian Inheritance in Man: A Catalog of Human Genes and Genetic Disorders. 12th ed. Johns Hopkins University Press; 1998:xl, xlii.