John Doe
WordNet
noun
(1) An unknown or fictitious man who is a party to legal proceedings
(2) A hypothetical average man
WiktionaryText
Proper noun
- A fictitious name used in the legal documents for an unknown or anonymous male person.
- Any unknown or anonymous male person.
- 1885: i.e. "to Tom, Dick or Harry:" the names like John Doe and Richard Roe are used indefinitely in Arab. — The Book of the Thousand Nights and a Night, Vol. 4 Footnote 5, Richard Burton