According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 25 words with the pattern ---N--ON-. That is, nine letter words with 4th letter N and 7th letter O and 8th letter N. In alphabetical order, they are:
canneloni
cannelons
chanfrons
cinnamons
cinnamony
cornstone
frontoons
grandsons
hornstone
irenicons
ironstone
magnetons
moonstone
planktons
quinolone
scansions
scontions
shankbone
sponsions
spontoons
trunnions
turnstone
veinstone
vignerons
whinstone