The verdict? This edition of Stedman's, with its pluses measured against its minuses, is clearly in the front of its class. The evidence? Read on.

Recent compilers of medical dictionaries have faced a daunting task. The medical sciences, especially biochemistry, genetics, and immunology, have grown vigorously in the past two or three decades, and their vocabularies have grown, too. For the lexicographer, just identifying new words, phrases, symbols, and abbreviations in such fields is relentless work. That this new Stedman's, with its size and complexity, has appeared only 5 years after the preceding edition is proof of how indispensable computer technologies have become in publishing. But speed alone does not account for Stedman's front-place position.

First, the pluses

Stedman's appears to have kept up with exploding vocabularies. For example, "sequence-tagged site," "contig," and "transgene" have been brought in from genetics. A search through the latest five or six issues of Cell might turn up a genetics term or two not included, but that would be of no moment. Experts in fields such as genetics learn new terms well before the broad clinical audience does, but lexicographers have to be sure that new terms are likely to remain in use before they can admit them to a dictionary.

One of the primary difficulties for many users of a scientific dictionary is finding definitions for multiword terms. The 25th edition included a "Subentry Locator" that directed the user to the entry or entries in which a subentry term would be found; for example, "aborted ectopic" directed one to "pregnancy." In the 26th edition, this section (now named "Wordfinder") has been noticeably expanded. The explanation for its users is clear, as is its counterpart in the "User's Guide."

Another plus is the new device that clearly marks in the vocabulary (main) section the many Greek and Latin prefixes and suffixes of medical English. These determine the meaning of a huge fraction of English terms in medicine. Knowing the meaning of these prefixes and suffixes greatly aids medical students in their grasp of much of the vocabulary they will use.

Probably the best gain is in the number and quality of illustrations. These schematic, diagrammatic, and photographic illustrations, many in color, will clarify for many readers what is said in the partner definitions. The many tabular summaries are equally valuable.

But there are minuses. When medical writing is increasingly plagued with abbreviations, the meanings of which are too often known only to the insiders in a field, one can reasonably expect a dictionary to adhere to the lexicographic principle of defining a term at the complete form of the term and not at its abbreviation. This principle is justified because it keeps alive full formal terms, which tend to be definitions in themselves; it does not let them sink into obscurity in favor of abbreviations that carry no explanatory elements. This new Stedman's violates this principle when it defines "acquired immunodeficiency syndrome" at "AIDS," not at the unabbreviated term (which is represented by the only partially abbreviated term under "syndrome": "acquired immunodeficiency s., SYN AIDS)." This violation is not wreaked on "DNA," which is followed only by "Abbreviation for deoxyribonucleic acid"; the definition is found at "deoxyribonucleic acid." The dictionary's preface states that "a dictionary may suggest standards, but it cannot enforce them." Perhaps the definition of AIDS is the only one that violates this principle—that is to be hoped.

Another flaw for those of us who believe that medical writers and publishers should obey style conventions firmly established in other scientific fields is the dictionary's failure to italicize single-letter symbols that stand for quantities or variables. This convention is well established in many other fields, including physics, meteorology, and physical chemistry, and it is a central point in many International Organization for Standardization standards; it is also observed in many European medical journals. Examples of this violation in Stedman's are "V" rather than "V" for volume and "P" rather than "P" for pressure. Again, we see inconsistent violation of this style rule: "G" is given for the "Newtonian constant of gravitation" and, just below, "G" is given for "Gibbs free energy." I must point out that Stedman's does adhere to the international convention of italicizing certain kinds of taxonomic names, such as "Escherichia coli."

A curious innovation in this edition is the designating of "high profile terms," which are both listed in a front section and marked in the vocabulary section. We get no clear explanation of the basis that has been used to select such terms for "high profiling." Why is "prion" more "high profile" than "coronary artery bypass surgery"? And, indeed, what is the value of knowing that a term has a high profile?

To close as I opened: Adding up the score, I conclude that this edition of Stedman's is at the head of its class. There are pluses and minuses. But the 27th edition could be even better.

Edward J. Huth, MD

University of Pennsylvania

Philadelphia, PA 19104