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Topic: Names of polygons
Replies: 26   Last Post: Apr 29, 2008 12:08 PM

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John Conway

Posts: 2,238
Registered: 12/3/04
Re: 11-gon
Posted: Oct 24, 1994 5:35 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

I'm working my way back through all this email. I see that
"undecagon" and "duodecagon" have been rearing their ugly
heads again. The full set is

monogon, digon, trigon, tetragon, pentagon, hexagon, heptagon, octagon

(of which monogon and digon can only be used in rather special circumstances;

it's digon not "bigon"; and trigon and tetragon are alternatives to "triangle"
and "quadrilateral" - the adjectival forms "trigonal" and "tetragonal"
being more common), then

enneagon, decagon, hendecagon, dodecagon, triskaidecagon, tetrakaidecagon,...


nonagon undecagon duodecagon

but tridecagon and tetradecagon (&c)
are OK.

The (synonymous) words "triskaidecaphobia" and "tridecaphobia"
appear in dictionaries (occasionally spelled with a "k" instead
of that "c"). I was reminded of them in O'Hare airport yesterday,
as I passed gates 10,11,12,14,15,... !

John Conway

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