Unidentified decedent (also abbreviated as UID or UP) is a term in American English used to describe a corpse of a person whose identity cannot be established by police and medical examiners. In many cases, it may be several years before the real-life identities of some individuals are found, while in some cases, they are never identified. An individual may remain unidentified due to lack of evidence as well as absence of personal identification such as a driver's license.