John Doe

fictitious plaintiff in a legal action, attested from 1768 (in Blackstone). The fictitious defendant was Richard Roe. If female, Jane Doe, Jane Roe. Replaced earlier John-a-nokes (1530s) or Jack Nokes, who usually was paired with John-a-stiles or Tom Stiles. Also used of plaintiffs or defendants who have reason to be anonymous. By 1852, John Doe was being used in North America for "any man whose name is not known," but Britain tended to preserve it in the narrower legal sense "name of the fictitious plaintiff in actions of ejectment." John Doe warrant attested from 1935.

Also, John Q. Public; Joe Blow; Joe Doakes; Joe Zilch. An average undistinguished man; also, the average citizen. For example, This television show is just right for a John Doe, or It's up to John Q. Public to go to the polls and vote. Originally used from the 13th century on legal documents as an alias to protect a witness, John Doe acquired the sense of “ordinary person” in the 1800s. The variants date from the 1900s. Also see Joe six-pack.

Also, Jane Doe. An unknown individual, as in The police found a John Doe lying on the street last night, or The judge issued a warrant for the arrest of the perpetrators, Jane Doe no. 1 and Jane Doe no. 2. [Second half of 1900s]