Our last tip quoted a letter from a reader who objected to our recommendation that the term "Down syndrome" be used instead of "Down's syndrome." Dorland's Illustrated Medical Dictionary, he said, "lists 'Down's syndrome' and not 'Down syndrome.'" Further, he said, the "better designation is trisomy 21 syndrome."

We appreciate the reader's information, but it reveals a problem with many "better designations": Most members of the general public, we suspect, are unfamiliar with the term trisomy 21 syndrome. To make your meaning intelligible to a nonprofessional, everyday audience, you should probably put your faith in a mainstream authority such as Webster's Collegiate or the Random House dictionary. At the very least, this should suffice to shield one's posterior from partisan snipers.

Beyond that, writers dealing with an audience of specialists should try to ascertain what source that audience considers most authoritative, be it Dorland's Illustrated Medical Dictionary, another specialized or general-use reference, the Internet, or the local oracle.