Quick definitions from WordNet (joke)
▸ noun: a triviality not to be taken seriously ("I regarded his campaign for mayor as a joke")
▸ noun: a humorous anecdote or remark intended to provoke laughter ("He told a very funny joke")
▸ noun: a ludicrous or grotesque act done for fun and amusement
▸ noun: activity characterized by good humor
▸ verb: tell a joke; speak humorously ("He often jokes even when he appears serious")
▸ verb: act in a funny or teasing way
▸ Also see joke
▸ noun: a triviality not to be taken seriously ("I regarded his campaign for mayor as a joke")
▸ noun: a humorous anecdote or remark intended to provoke laughter ("He told a very funny joke")
▸ noun: a ludicrous or grotesque act done for fun and amusement
▸ noun: activity characterized by good humor
▸ verb: tell a joke; speak humorously ("He often jokes even when he appears serious")
▸ verb: act in a funny or teasing way
▸ Also see joke