a) A boxed snack consisting of caramel-coated popcorn and peanuts, well known for including surprise toys of nominal value.
Take me out to the ball game / Take me out with the crowd / Buy me some peanuts and Cracker Jack / I dont care if I never get back.
b) One kernel of the Cracker Jack snack.
A Cracker Jack fell to the theater floor.
Wikipedia foundation.