A more thorough explanation:

Definition: John Doe is a fake name used in legal cases when the real name of a person is not known. It can be used to protect the identity of a person or to stand in for an unknown defendant. In some cases, it is also used as a temporary name for an unidentified person in a hospital or morgue.

For example, if someone is injured in a car accident and the driver who caused the accident is not known, the injured person can file a lawsuit against "John Doe" until the real name of the driver is discovered. Similarly, if a person is admitted to a hospital without any identification, they may be given the name "John Doe" until their real identity is determined.

John Doe is usually used for males, while Jane Doe is used for females. Other variations of the name include Richard Roe, Jane Roe, Baby Doe, Janie Doe, and Johnny Doe for children.

Overall, John Doe is a useful tool in the legal system to protect the rights of individuals when their identity is not known or to preserve a claim until the real defendant can be identified.