[evil_twin]

Dictionary.com (hardly the worlds greatest authority) gave me the following:

a·the·ist n.One who disbelieves or denies the existence of God or gods.

I do deny the existence of God or gods, but for the sake of intellectual honesty I have to conceed that there is a tiny possibility that I am wrong. After all there is some pretty weird stuff out there, vis-à-vis relativity or particle based double slit experiments.

I would attribute approximately the same probability to god existing as I would to the tooth fairy existing though. We all basically know the tooth fairy doesn't exist, though we cannot utterly discount the chance that there is a weird tooth obsessed fairy type creature somewhere out there.

All in all I think it's still reasonable to call myself an athiest if the dictionary.com definition is accurate.