According to SOWPODS (the combination of Scrabble dictionaries used around the world) there are 8 words with the pattern -O-IAT---. That is, nine letter words with 2nd letter O and 4th letter I and 5th letter A and 6th letter T. In alphabetical order, they are:
foliating
foliation
foliature
goniatite
horiatiki
podiatric
sociation
sociative