🚀 go-pugleaf

It's my impression that `n-ary' is *much* commoner in math discourse that
ternary, etc. (one isn't often interested in the special case), so would
be the most likely source for `arity'.  Howbout `n-adic' -> `adicity'?

A model that the formation might be based on is `n ton' -> `tonnage',
e.g. numeral+measure_noun -> measure_noun+nominalizer, forming an
expression designating the amount present of whatever the measure noun
measures.  The hyphen in `n-ary' would make it considerably easier
for people to treat `ar' as if it were in effect a noun, more or
less synonymous with `place' in `n-place', placedness (??)).

Philologically, I guess the next step would be finding the first
attestation.  The date to beat seems to be 1979 (Boyer and Moore),
from ROK's posting.

  Avery Andrews (ada612@csc.anu.edu.au)