A challenge is a request made to the holder of a competitive title for a match between champion and challenger, the winner of which will acquire or retain the title. In some cases the champion has the right to refuse a challenge; in others, this results in forfeiting the title. The challenge system derives from duelling and its code of honour.
These days, social networking has been challenged by asking users of these networks to post photos of theirs 10 years ago.
While many competitive sports use some form of tournament to determine champions, a challenge match is the normal way of deciding professional boxing titles and the World Chess Championship