M3 or M-3 may be:

• Globular Cluster M3, a Messier object in the constellation Canes Venatici
• M3 motorway, a highway in England
• M3 motorway (Northern Ireland), a spur of the M2 motorway (Northern Ireland)
• M3 motorway (Republic of Ireland), a proposed upgrade to part of the N3 road
• M3 motorway (Hungary)
• Michigan State Highway 3
• M3 Grease Gun, a U.S. submachinegun
• M3 Lee, a U.S. Army tank of World War II. When built in Britain, it was named M3 Grant
• M3 Bradley, the cavalry fighting vehicle version of the U.S. M2 Bradley
• M3 Half-track, a widely used infantry transport in World War II
• BMW M3 automobile
• major third in music
• money supply, M3 refers to the amount of cash in circulation, the amount in checking or demand deposit accounts plus savings accounts, money market accounts, certificate of deposit accounts and foreign-currency holdings.
• M3 was the code name for a special U.S. military mission on Roosevelt Roads Naval Station, in Ceiba, Puerto Rico
• M3 is an obsolete BBC technical standard for calibrating stereo peak programme meters
• GBA Movie Player M3 adapter
• M3, the class name given to the updated Metropolitan class of electric multiple unit ("EMU") railroad cars built by the Budd Company in the early 1980s for the Metropolitan Transportation Authority (New York)'s Long Island Rail Road and the Metro North Railroad.
• ABSA - Aerolinhas Brasileiras, Air Service (airline) and Nordic Flying IATA airline designators

m3

• minor third in music

m³

• Cubic metre

See also

• 3M

M3 | M3 | M3 | M3 | M3 | M3 (olika betydelser)