cracker (Noun) — A thin crisp wafer made of flour and water with or without leavening and shortening; unsweetened or semisweet.
cracker (Noun) — A poor White person in the southern United States.
cracker (Noun) — A programmer who cracks (gains unauthorized access to) computers, typically to do malicious things. ex. "crackers are often mistakenly called hackers"
cracker (Noun) — Firework consisting of a small explosive charge and fuse in a heavy paper casing.
cracker (Noun) — A party favour consisting of a paper roll (usually containing candy or a small favour) that pops when pulled at both ends.
cracker (Noun) — An outstanding example of its kind.