Is a trust a corporation

I'm surprised there is nothing clear on the web already about this but Black's Law Dictionary's (5th Ed) several page definition of "corporation" does not contain the Word "trust" so I would think a trust cannot be considered a corporation. I'm curious since an American franchises frachise agreement containes the Words "if the corporation is a trust....", which I think is erroneous, based on lack of web clarity and Black's Law dictionary.