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2.
empty, containing or meaning nothing
Dude, we ate all of the pizza, there's jack taco left.
by Sarah March 10, 2004
 
1.
(1) adjective: meaning nothing or empty. Used by a specific World History teacher many times, and still gets a laugh from the naive children.
(1) "The Soviets had no idea that we were coming. They knew jack taco."
by THE ALL KNOWING AMY May 05, 2004