N3

N3 may refer to:

Roads

 * N3 (Bangladesh), connecting Dhaka and Mymensingh
 * N3 road (Belgium), one of the national roads in Belgium
 * National Road 3 (Democratic Republic of the Congo)
 * N3 road (Gabon)
 * N3 road (Ghana)
 * N3 road (Ireland), a National Primary Route
 * N3 motorway (Netherlands), one of the national roads in the Netherlands
 * N3 road (Senegal), one of the national roads in Senegal
 * N3 (South Africa), a road connecting Johannesburg to Durban
 * Route nationale 3, France

Transportation

 * N3-class battleship, a Royal Navy battleship design that was never built
 * USS N-3 (SS-55), a 1915 coastal defense submarine of the US Navy
 * SP&S Class N-3, a steam locomotives class from the Spokane, Portland and Seattle Locomotive Roster
 * N3, gauges for monitoring a third section in a triple spool jet engine


 * N3, IATA code for the Russian airline Omskavia
 * N3, European large goods vehicles above 12 tonnes

Science and technology

 * Haplogroup N (Y-DNA), a former human Y-chromosomal haplogroup, now N1c
 * n-3, Omega-3 fatty acid
 * Trinitrogen (N3), inorganic molecule composed of three nitrogen atoms
 * N3-, an azide anion in chemistry
 * N(3-), a nitride anion in chemistry
 * N3 Lung cancer, metastasis to certain lymph nodes
 * N3, the genus three non orientable surface
 * N3, cis-bis(isothiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylato)ruthenium(II), a red dye in dye-sensitized solar cells
 * N3, abbreviation for the 3 nanometer process node in semiconductor technology

Other

 * N3 (Calgary), condominium building
 * N3 (NHS), the national broadband network for the English National Health Service
 * Notation3, or N3 rules, a textual notation for the Resource Description Framework
 * N3, the third level of the Japanese-Language Proficiency Test
 * N3, the most recent version of the Nagravision conditional access system for cable and satellite television
 * N3, a postcode district in the N postcode area in London
 * N3, the former name of NDR Fernsehen, a German television channel