Nomen nescio

Nomen nescio, abbreviated to N.N., is used to signify an anonymous or non-specific person. From Latin nomen, name, and nescire, not to know, be ignorant of. Together, I do not know the name.

One use for this name is to protect against retaliation when reporting a crime or company fraud. In the Netherlands a police suspect that refuses to give his name is given an "N.N. number." In Germany, and Belgium, N.N. is also frequently seen in university course lists, indicating that a course will take place but that the lecturer is not yet known; the abbreviation is sometimes explained as "nomen nominandum" ("the name is to be announced") in this case.

N. N. is commonly used in the scoring of chess games, not only when one participant's name is genuinely unknown but when an untitled player faces a master, as in a simultaneous exhibition.

The generic name Numerius Negidius used in Roman times was chosen partly because it shared initials with this phrase.

Genealogists often use the abbreviation to signify an unknown or partially unknown name (such as N.N. Jones).