(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
empty, containing or meaning nothing
Dude, we ate all of the pizza, there's jack taco left.
by Sarah March 10, 2004