A delegate is an individual (or a member of a group called a delegation) who represents the interests of a larger organization (e.g. a government, a charity, an NGO, or a trade union) at a meeting of some kind (e.g. trade talks, an environmental summit, aid negotiations, or an industrial dispute).
In order to avoid the principal-agent problem, it is generally important to the organization to take steps to insure that the delegate or delegation does not have a conflict of interest. Failure to do so may reduce the chances of the organization's viewpoint being represented as well as possible.
