Nonagon or Enneagon?
Date: 02/06/2003 at 11:21:05 From: David Subject: 9-sided polygons I noticed in Conway's post Naming Polygons http://mathforum.org/library/drmath/view/57666.html that "nonagon" is not the correct name for a 9-sided polygon. Every textbook I've referred to uses it, however. Is "enneagon" really the correct name? If so, why do all of the textbooks have it wrong?
Date: 02/06/2003 at 12:10:01 From: Doctor Peterson Subject: Re: 9-sided polygons Hi, David. Dictionaries, too, usually list "nonagon" and "undecagon" rather than Conway's preferred "enneagon" and "hendecagon," if they list either. That's because they are "descriptive," telling how people actually use words, rather than being "prescriptive," telling how they would use words if they were intelligent. ;-) The fact is that English has never been as consistent as people like Dr. Conway and me, who enjoy the study of etymology, wish it were. I note that Merriam-Webster explains the origin of "nonagon" this way: Latin nonus ninth + English -gon This avoids the fact that "-gon" ultimately comes from Greek, making this a sort of hybrid that irritates purists; but it is probably realistic to recognize that words like this are invented in English, and are thought of as made from English roots, not from Latin and Greek. Since people are far more familiar with "nona-" than with "ennea-", it is natural that the former seems obviously right to all but the most knowledgeable. So keep using "nonagon"; in practice there's nothing wrong with it. But if you like idealistic campaigns, you may get on the "enneagon" bandwagon with us; there's plenty of room aboard! If you have any further questions, feel free to write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/
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