A measure of surety to the extent that you would eat a hat. If you are proven wrong you must eat a paper hat. The size of the paper hat corresponds to the level of surety you expressed. (A5 hat sure is less sure than A4 hat sure but A4 is usually the standard.)
"I'm pretty sure that Walt Disney is frozen..."

"Are you hat sure?"

"Yes."

"How hat sure? A4 hat sure?"

"Yes."

"Well you are wrong, now eat this paper hat I've made for you."
by DiosaTaylor May 30, 2013
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