Richard Nixon, 37th President of the United States

Radon (chemical symbol: Rn), a chemical element with the atomic number 86

Royal Navy

Registered nurse

Rio Grande do Norte (ISO 3166-2:BR code: RN), a state in Brazil

Route Nationale (France), trunk road

Radio Nederland

Radio National, an Australia-wide radio network broadcast by the Australian Broadcasting Corporation

rn (newsreader), a unix Usenet news client

Renovación Nacional ("National Renewal"), a Chilean political party of the center-right

Air Horizons (IATA code: RN), an airline based in Paris, France

Province of Rimini (ISO 3166-2:IT code: RN), a province in the Emilia-Romagna region of Italy

Registered Identification Number, a number issued by the Federal Trade Commission, used on clothing tags and labels

Reference noise