Inside joke or a private joke is a joke that is understood by only a select number of people inside a certain social group.
Those on the outside of the group that understands the joke usually don't have any clue as to what it actually means. In many cases, it's just a word or a phrase that refers back to some humorous situation.
For example, an inside joke can be as simple as repeating something one of the participants in the activity said. The other participants are likely to find this funny while outsiders from the shared activity won't understand the significance of the words.
Even when the insiders explain the joke to the outsiders, the humor may not be fully appreciated since the memory of the shared situation adds to the meaning of the joke.
Those on the outside of the group that understands the joke usually don't have any clue as to what it actually means. In many cases, it's just a word or a phrase that refers back to some humorous situation.
For example, an inside joke can be as simple as repeating something one of the participants in the activity said. The other participants are likely to find this funny while outsiders from the shared activity won't understand the significance of the words.
Even when the insiders explain the joke to the outsiders, the humor may not be fully appreciated since the memory of the shared situation adds to the meaning of the joke.