Is petted a word

Petted is a Word.

I got into a debate with my six year old daughter about this today. It shows up in the online dictionary, http://www.thefreedictionary.com/petted , and in an old 1984 Webster dictionary. Petted is definitely a Word.

petted is not a Word

No it is pronounced pet because petted doesn't make since when you say you petted the dog. When you say I pet the dog it makes more sense.

I beg to differ, when you say "I pet the dog." it implies present tense or something you would do now. Using pet in a different way one could say "I was petting the dog." But for some sentences petted would be appropriate, "The dog was petted yesterday." is grammatically correct especially when compared to "The dog was pet yesterday." As you can probably see, the second variation implies present tense but does not agree with the tense implied by yesterday. Lastly, one who really wishes to explore this topic might check any dictionary under the inflected forms of the verb pet.