ˌJohn ˈDoe noun [uncountable and countable]
American English used especially by the police to refer to a man whose name is not known ⇒ Jane Doe

[TahlilGaran] Dictionary of Contemporary English ▲

John Doe
[American]
a man or boy whose real name must be kept secret or is not known, especially in a court of law.
The patient was referred to in court documents as John Doe.

[TahlilGaran] English Idioms Dictionary ▲

John Doe
a name used for an unknown/average person
The application forms use the name "John Doe" as the name of a person who is applying for something.

[TahlilGaran] English Idioms Dictionary ▲

john doe
n. A name used for an unknown person, especially in police and law business.
The alarm went out for a John Doe who stole the diamonds from the store.

[TahlilGaran] English Idioms Dictionary ▲