a name used in law courts, legal papers, etc. to refer to a person whose actual name is unknown, esp. to the second person of two when both names are unknown (the first person being referred to as John Doe)
See Richard Roe in American Heritage Dictionary 4
(rĭchˈərd rō)
noun
Used as a name in legal proceedings to designate an unknown or unidentified man or boy, especially the second of two such persons, the first usually being named John Doe.