Definition of cracker noun from the Oxford Advanced Learner's Dictionary

cracker

noun
ˈkrækə(r)
 
; ˈkrækər
 
 
1 a thin dry biscuit that is often salty and usually eaten with cheese see also cream cracker, graham cracker2 (also Christmas cracker) a tube of coloured paper that makes a loud explosive sound when it is pulled open by two people.Crackers usually contain a paper hat, a small present and a joke, and are used in Britain at Christmas parties and mealsWho wants to pull this cracker with me? see also firecracker3 (British English, informal) something that you think is very good, funny, etcIt was a cracker of a goal.I've got a joke for you. It's a real cracker!4 (North American English, slang) an offensive word for a poor white person with little education from the southern US5 (informal) a person who illegally finds a way of looking at or stealing information on somebody else's computer system6 (old-fashioned, British English, informal) an attractive woman